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VIVISECTION
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VIVISECTION , literally the cutting (sectio) of living (vivus) animals, a word which might be applied to all surgical operations whether practised upon the See also:lower animals or on See also:man. As conventionally used, however, it has exclusive reference to experiments upon the lower animals undertaken for the See also:advancement of medical sciences. There are a number of See also:people who, calling themselves See also:anti-vivisectionists, strongly See also:object to these experiments on the lower animals; and it must be conceded that the humane reasons which they advance against it can only be set aside as " sentimental " if considerations of a wider humanity can show that the arguments of the anti-vivisectionists really run See also:counter to human progress. The supporters of vivisection, properly considered, must not be confused with those who would make a barbarous use of this means of See also:research. What is at stake here is the right to use it properly and at all. It would be possible for See also:cruelty of an unnecessary See also:kind to result if the practice of vivisection were unrestricted; and the purpose of this See also:article is to give some See also:account of the method of experiments on animals as sanctioned by See also:law in the See also:United See also:Kingdom, and to justify that method by setting forth the See also:chief See also:historical discoveries that have been made by the help of vivisection. Such experiments have for their object the advancement of the sciences of See also:physiology and See also:pathology. From the earliest periods experimental vivisections have occasionally been practised, but before the days of anaesthetics it was difficult to execute them,•and not less difficult to draw conclusions. The invention of anaesthetics has greatly extended the See also:scope of the experimental method, because an See also:animal can be kept unconscious and quiet, without even a See also:quiver of a•muscle, during prolonged operations. Further, the introduction of the antiseptic method has made it possible to subject all tissues and regions of the See also:body to surgical interference, and this has also had the effect of increasing the possibilities of experimental research. In 1906 a See also:British Royal See also:Commission was appointed to inquire into the whole subject under the chairmanship of See also:Lord See also:Selby, on whose See also:death Mr A. J. See also:Ram, K.C., took the See also:chair. The Commission sat from See also:October 1906 to See also: The act, therefore, was drafted with a view to physiology, without much concern for pathology, and without foreknowledge of bacteriology. At the time of See also:writing (191o), 95% of the experiments are inoculations. Every experiment must be made in a registered See also:place open to See also:government inspection. But inoculation experiments are sometimes permitted in non-registered places, for the immediate study of outbreaks of disease, or in circumstances which render it impracticable to use a registered place. Every experiment must be made under a See also:licence; and every application for a licence must be recommended by the signatures of two out of a small body of authorities specified in the act—presidents of certain learned See also:societies and professors of certain See also:universities and colleges. The word " experiment " is not allowed to See also:cover the use of more than one animal. Most experiments are made not under a licence alone, but under a licence plus one or more certificates, and the wording and working of these certificates must be clearly understood, because it is over them that the question arises as to the amount of See also:pain inflicted by these experiments. Under the licence alone, the animal must be kept under an anaesthetic during the whole of the experiment; and " if the pain is likely to continue after the effect of the anaesthetic has ceased, or if any serious injury has been inflicted on the animal," it must be killed forthwith under the anaesthetic. Thus, under the licence alone, it is impossible to make an inoculation; for the experiment consists, not in the introduction of the See also:needle under the skin, but in the observation of the results of the inoculation. A See also:guinea-See also:pig inoculated with tubercle cannot be kept under an anaesthetic till the disease appears. The disease is the experiment, and it is therefore an experiment made without an anaesthetic, and not authorized by the licence alone. Again, under the licence alone it would have been impossible to work out the See also:thyroid treatment of See also:myxoedema, or the facts of cerebral localization. For to remove the thyroid gland, or to remove a portion of the See also:surface of the See also:brain, is to inflict a serious injury on the animal. The operation is done under profound See also:anaesthesia—it would be impracticable otherwise; the See also:wound is treated and dressed by the antiseptic method—suppuration would invalidate the result. But a serious injury has been inflicted. Nevertheless, the animal must not be killed forthwith: the result must be watched. These and the like experiments cannot therefore be made under the licence alone. For the removal of such disabilities as these, the act empowers the See also:home secretary to allow certain certificates, to be held with the licence. They must be recommended by two signatures, and various restrictions are put upon them by the home secretary. On July s1, 1898, the home secretary was asked, in the See also:House of See also:Commons, what were the conditions and regulations attached by the Home See also:Office to licences and certificates; and he answered " The conditions are not always the same, but may vary according to the nature of the investigation. It is hardly possible, therefore, for me to See also:state all the conditions attached to licences and certificates. The most important conditions, however (besides the limitations as to place, time and number of experiments), and the conditions most frequently imposed, are those as to See also:reporting and the use of See also:antiseptics. The latter See also:condition is that the animals are to be treated with strict antiseptic precautions, and if these fail and pain results, they are to be killed Immediately under anaesthetics. The reporting conditions are, in brief, that a written See also:record, in a pre-scribed See also:form, is to be kept of every experiment, and is to be open for examination by the inspector; that a See also:report of all experiments is to be forwarded to the inspector; and that any published account of an experiment is to be transmitted to the secretary of state. Another condition requires the immediate destruction under anaesthetics of an animal in which severe pain has been induced, after the See also:main result of the experiment has been attained." The home secretary attaches to licences and certificates such endorsements as he thinks See also:fit. The See also:bare See also:text of the act, now See also:thirty-four years old, is a very different thing from the See also:administration of the act; and the present writer is in a position to say that the act is administered with See also:great strictness, under a careful See also:system of inquiry and reference. The certificates are distinguished as A, B, C, E, EE and F. Certificate D, which permitted the testing, by experiments, of " former discoveries alleged to have been made," has fallen into disuse. Certificate C permits experiments to be made by way of See also:illustration of lectures. They must be made under the provisions contained in the act as to the use of anaesthetics. Certificates E and EE permit experiments on See also:dogs or See also:cats; certificate F permits experiments on horses, asses or mules. These certificates are linked with Certificate A or Certificate B. It is See also:round these two certificates, A and B, that the controversy as to the pain caused by experiments on animals is maintained. Certificate A permits experiments to be made without anaesthesia. It is worded as follows: " Whereas A. B. of [here insert address and profession] has represented to us (i.e. two authorities) that he proposes, if duly authorized under the above-mentioned act, to perform on living animals certain experiments described below: We hereby certify that, in our See also:opinion, insensibility in the animal on which any such experiment may be performed cannot be produced by anaesthetics without necessarily frustrating the object of such experiment." All inoculations under the skin, all feeding experiments and the like, are scheduled under this certificate. They must be scheduled somehow: they cannot legally be made under a licence alone. Though the only See also:instrument used is a hypodermic needle, yet every inoculation is officially returned as an experiment, calculated to give pain, performed without an anaesthetic. It is for inoculations and the like experiments, and for them alone, and for nothing else, that Certificate A is allowed (or A linked with E or F). This want of a See also:special certificate for inoculations, and this wresting of Certificate A for the purpose, have led to an erroneous belief that " cutting operations' are permitted by the act without an anaesthetic. But, as the home secretary said in See also:parliament, in March 1897, " Certificate A is never allowed except for inoculations and similar trivial operations, and in every See also:case a condition is attached to prevent unnecessary pain." And again he wrote in 1898, Such special certificates (dispensing with anaesthetics) are granted only for inoculations, feeding and similar procedures involving no cutting. The animal has to be killed under anaesthetics if it be in pain, so soon as the result of the experiment is ascertained." Certificate B permits the keeping alive of the animal after the initial operation of an experiment. It is worded as follows: " Whereas A. B. of [here insert address and profession] has represented to us (i.e. two authorities) that he proposes, if duly authorized under the above-mentioned act, to perform on living animals certain experiments described below, such animals being, during the whoie of the initial operation of such experiments, under the See also:influence of some anaesthetic of sufficient See also:power to prevent their feeling pain: We hereby certify that, in our opinion, the killing of the animal on which any such experiment is performed before it recovers from the influence of the anaesthetic administered to it would necessarily frustrate the object of such experiment." Certificate B (or B linked with EE or F) is used. for those experiments which consist in an operation plus subsequent observation of .the animal. The See also:section of a See also:nerve, the removal of a secretory See also:organ, the See also:establishment of a See also:fistula, the plastic surgery of the See also:intestine, the sub-dural method of inoculation—these and the like experiments are made under this certificate. We may take, to illustrate the use of Certificate B, See also:Horsley's observations on the thyroid gland. The removal of the gland was the initial operation; and this was performed under an anaesthetic, and with the antiseptic method. Then the animal was kept under observation: The experiment is neither the operation alone nor the observation alone, but the two together. The purpose of this certificate is set forth in the inspector's report for 1909. " In the experiments performed under Certificate B, or B linked with EE, 1704 in number, the initial operations are performed under anaesthetics from the influence of which the animals are allowed to recover. The operations are required to be performed antiseptically, so, that the healing of the wounds shall, as far as possible, take place without pain. If the antiseptic precautions fail, and suppuration occurs, the animal is required to be killed. It is generally essential for the success of these experiments that the wounds should heal cleanly, and the surrounding parts remain in a healthy condition. After the healing of the wounds the animals are not necessarily, or even generally, in pain, since experiments involving the removal of important See also:organs, including portions of the brain, may be performed without giving rise to pain after the recovery from the operation; and after the section of a part of the See also:nervous system, the resulting degenerative changes are painless. In the event of a subsequent operation being necessary in an experiment performed under Certificate B, or B linked with EE, a condition is attached to the licence requiring all operative procedures to be carried out under anaesthetics of sufficient power to prevent the animal feeling pain; and no observations or stimulations of a See also:character to cause pain are allowed to be made without the animals being anaesthetized. In no case has a cutting operation more severe than a superficial venesection (the opening of a vein just under the skin) been allowed to be performed without anaesthetics." From this brief account of the chief provisions of the act, we come to consider the general method of experiments on animals in the United Kingdom, and the question of the infliction of pain on them. The figures for a representative See also:year may be given. The See also:total number of licensees in 19o9r in See also:England and See also:Scotland, was 483: of whom 135 performed no experiments during the year. The total number of experiments was 86,277, being 2357 less than in 1908. They were made as follows : Under Licence alone . Certificate C . Certificate A . Certificates A+E Certificates A+F Certificate B Certificates B +EE Certificate F . . The experiments performed under Certificate A (or A+E, or A+F) were mostly inoculations; but a few were feeding experiments, or the administration of various substances by the mouth or by inhalation, or the See also:abstraction of See also:blood by puncture or by See also:simple venesection. Inoculations into deep parts, involving a preliminary incision, are required to be per-formed under anaesthetics (Certificate B). " It will be seen," says the report for 1909, " that the operative procedures in experiments performed under Certificate A, without anaesthetics, are only such as are attended by no considerable, if appreciable, pain. The certificate is, in fact, not required to cover these proceedings, but to allow of the subsequent course of the experiment. The animals most used for inoculations are mice, rats, guinea-pigs and rabbits. It is not once in a thousand times that a See also:dog or a See also:cat is used for inoculation. The act of inoculation is not in itself painful. A small See also:area of the skin is carefully shaved and cleansed, that it may be aseptic, the hypodermic needle is sterilized and the method of hypodermic injection or of See also:vaccination is the same as it is in medical practice. "A guinea-pig that will See also:rest quietly in your hands before you commence to inject it, will remain perfectly quiet during the introduction of the needle under the skin; and the moment it is returned to the cage it resumes its interrupted feeding. See also:Arteries, See also:veins and most of the parts of the viscera are without the sense of See also:touch. We have actual See also:proof of this in what takes place when a See also:horse is bled for the purpose of obtaining curative serum. With a See also:sharp See also:lance a cut may be, made in the skin so quickly and easily that the animal does nothing more than twitch the skin-muscle of the See also:neck, or give his See also:head a shake, while of the further proceeding of introducing a hollow needle into the vein, the animal takes not the slightest See also:notice. Some horses, indeed, will stand perfectly quiet during the whole operation, munching a See also:carrot, nibbling at a wisp of See also:hay, or playing with a See also:button on the vest of the See also:groom See also:standing at its head." These sentences, written in the Medical See also:Magazine (See also:June 1898) by Dr See also:Sims Woodhead, See also:Professor of Pathology at See also:Cambridge, are sufficient evidence that inoculations and the like experiments are not painful at the time. In a few instances cultures of micro-organisms have been made in the anterior chamber, of the See also:eye, by the introduction of a needle behind the cornea. This might be thought painful, but See also:cocaine renders the surface of the eye wholly insensitive. Many operations of opfithalmic surgery are done under cocaine alone, and the anterior chamber of the eye is so far insensitive that a man may have blood or pus (hypopyon) in it, and hardly be conscious of the fact. The results of inoculation are in some cases negative, in others See also:positive; the positive results are, in the great majority of cases, not a See also:local See also:change, but a general infection which may end in recovery, or in death. The diseases thus induced may, in many cases, fairly be called painless—such are septicaemia in a See also:mouse, snake-venom in a See also:rat, and See also:malaria in a See also:sparrow. Rabbits affected with rabies do not suffer in the same way as dogs and some other animals, but become subject to a painless kind of See also:paralysis. It is probable that animals kept for inoculation have, on the whole, less pain than falls to the See also:lot of a like number of animals in a state of nature or in subjection to work: they are well fed and sheltered, and See also:escape the rapacity of larger animals, the inevitable cruelties of See also:sport, and the drudgery and sexual See also:mutilation that man inflicts on the higher domestic animals. The present writer has, of course, seen the mice that are used for the study of See also:cancer (Imperial Cancer Research Fund), and the guinea-pigs that are used at the See also:Lister See also:Institute for thetesting of the London See also:milk-See also:supply, lest the milk should convey tubercle. He did not see, among all the many animals, one that appeared to be suffering: See also:save that a very few of the mice were incommoded, or, if the word be applicable to mice, distressed, by large tumours. Of the guinea-pigs that had been inoculated, not one seemed to be in any pain. A nodule of tubercle, or a tuberculous gland, is painless in us, and therefore cannot be painful in a guinea-pig. It is not denied that the study of some diseases (See also:plague, See also:tetanus) causes some pain to rats and rabbits; but this pain is hardly to be compared with the pain and horror of these diseases in man. We come now to Certificate B. If it were lawful, under Certificate B, to make an incision under an anaesthetic, to See also:call this the " initial operation," and then, without an anaesthetic, to make painful experiments, through the incision, on the deeper structures, doubtless much pain might be inflicted under this certificate. But experiments of this kind can be, and are, made under the licence alone, the animal being kept under an anaesthetic all the time, and killed under it. " No experiments requiring anything of the nature of a surgical operation, or that would cause the infliction of an appreciable amount of pain, are allowed to be performed without an anaesthetic" (Inspector's Report for 1899). " These certificates (B) are granted on condition that antiseptic precautions are used; and if these fail, and pain continues after the anaesthetics have ceased to operate, the animal is immediately killed painlessly" (See also:Letter from the Home Secretary, 1898). Of experiments made under this certificate (which must be linked with Certificate EE for any experiment on a dog or a cat), three instances may be given here: an operation on the brain, a removal of part or the whole of a secreting gland, and the establishment of a fistula. It is to be noted that, for these and the like operations, profound anaesthesia and the strict observance of the antiseptic method are matters of See also:absolute See also:necessity for the success of the experiment: the operation could not be performed without anaesthesia; and the experiment would come to nothing if the wound suppurated. It is to be noted, also, that these operations are such as are performed in surgery for the saving of See also:life or for the See also:relief of pain. As to operations on the brain, it must be remembered that the surface of the brain is not sensitive. Therefore the removal or destruction, of a portion of the surface of the brain, or the See also:division of some See also:tract of central nervous See also:tissue, though it might See also:entail some loss of power or of See also:control, does not, cause pain: a wound of the brain is painless. Tension within the ;See also:cranial cavity, as in cases of cerebral See also:tumour or cerebral See also:abscess, may indeed cause great pain; and, if the aseptic method failed, in an experiment, inflammation and tension would ensue: in that case the animal must be killed.
The removal of part or the whole of a secreting gland (e.g. the thyroid, the See also:spleen, the See also:kidney) is performed by the same methods, and with the same precautions, as in human surgery. Profound anaesthesia, and the use of a strict antiseptic See also:procedure, are of absolute necessity. The skin over the part to be removed must be shaved and carefully cleansed for the operation; the See also:instruments, See also:sponges and ligatures must be sterile, not capable of infecting the wound; and when the operation is over, the wound must be carefully closed with sutures, and See also:left to heal under a proper surgical dressing.
The establishment of a fistula, again, is an operation practised, as a See also:matter of course, in large See also:numbers of surgical cases. The See also:stomach, the See also:gall-See also:bladder, the large intestine, are opened for the relief of obstruction, and kept open, either for a time or permanently, according to the nature of the case. Under anaesthesia, the organ that is to be opened is exposed through an incision made through the structures overlying it, and is secured in the wound by means of See also:fine sutures. Then, when it has become adherent there, it is opened by an incision made into it; no anaesthetic is needed for this purpose, because' these See also:internal organs are so unlike the skin in sensitiveness that an incision is hardly See also:felt : the patient may say that he " felt a -prick," or he may be wholly unconscious that anything has been done. A
1,980
196
81,566
595
1,385
319
8
fistula thus established is not afterward painful, though there may be some discomfort now and again.
The classical instance is the case of See also:Alexis St See also: He let Dr See also:Beaumont make experiments on him for nine years: " During the whole of these periods, from the See also:spring of 1824 to the present time (1833), he has enjoyed general See also:good See also:health . . . active, athletic and vigorous; exercising, eating and drinking like other healthy and active people. For the last four months he has been unusually plethoric and robust, though constantly subjected to a continuous See also:series of experiments on the interior of the stomach; allowing to be introduced or taken out at the See also:aperture different kinds of See also:food, drinks, elastic catheters, thermometer tubes, gastric juice. chyme, &c., almost daily, and sometimes hourly. Such have been this man's condition and circumstances for several years past; and he now enjoys the most perfect health and constitutional soundness, with every See also:function of the system in full force and vigour " (Beaumont, Experiments and Observations on the Gastric Juice, 1838). We come now to the question, What anaesthetics are used in these experiments, and are they properly administered? The anaesthetics used are—(r) See also:chloroform, See also:ether, or a mixture containing chloroform and ether; (2) morphia, See also:chloral, See also:urethane. It is sometimes said that morphia is not an anaesthetic. That depends on the quantity given. Not a See also:month passes in this See also:country without somebody killing himself or herself with morphia or chloral. They See also:die profoundly anaesthetized: they cannot,be roused; even the pain of a strong electric See also:shock is not enough to rouse them. So it is with animals. The doses given to them are enormous and produce See also:complete insensibility. On this point the evidence given before the Royal Commission of 1906-8 by Mr Thane, Professor Schafer, See also:Sir See also:Lauder See also:Brunton, Sir See also: The effect of that is, that the dog becomes sleepy and stupid, and then sometimes it will lie down quietly, and if it is very sleepy you can put a See also:mask over its See also:nose containing the chloroform, alcohol and ether mixture, which it takes quite quietly. If, at the time one wants to begin the operation, the animal is not fully under the influence of morphia —if it still seems restless—it is put in a See also:box, and there it has some See also:wool saturated with the A.C.E. mixture put in the box. The See also:air gradually gets saturated, the dog gets more and more sleepy, and finally subsides at the bottom of the box." A few words must be said here about curare. It was said, some years ago, by an opponent of experiments on animals, that " curare is used daily throughout England," whereas, it is seldom used at all, and is never used alone in any sort or kind of operation on any animal in this country: in every such case a recognized anaesthetic must be given, and is given. In large doses curare not only abolishes the See also:movement of the voluntary muscles,. but also acts as an anaesthetic: in small doses it acts only on the voluntarymuscles, i.e. on the endings of the motor nerves going to these muscles. For example, suppose that the object of the experiment is to observe and record the action of a nerve on the contraction of certain blood vessels. The nerve gives off some branches to muscles, and other branches to blood vessels. If the animal be anaesthetized, and the nerve. stimulated, muscles and vessels will both See also:contract; but, if curare be given, as well as an anaesthetic, the vessels alone will contract, without the muscles: for curare does not act on the endings of motor nerves going to blood vessels. But, as a See also:practical matter, curare is very hard to obtain, and is often impure, and is very seldom used. One of the inspectors said to the Royal Commission that he had once seen it used, fifteen years ago. Professor Gotch said that he had not used it, in his own work, for twenty years. Professor Schafer said that he had not used it for years. And Sir Lauder Brunton said that he did not think he had used it at all since the passing of the act of 1876. The fear that, in a case where curare was being used, the effect of the anaesthetic might " pass off," and the animal be left under curare alone, is not reasonable. The dosage and administration of anaesthetics is not left to See also:chance. If, for example, an animal is receiving a definite percentage of chloroform vapour, it is of necessity under the influence of the chloroform: and the anaesthesia will gradually become not less but more profound. (See the evidence given before the Royal Commission by Professor See also:Langley and Professor See also:Waller.) It may be interesting to compare the pain, or death, or discomfort among 86,277 animals used for experiments in Great See also:Britain in 1909, with the pain, or death, or discomfort of an equal number of the same kinds of animals, either in a state of nature, or kept for sport, or used for the service of human profit or amusement. But it would be outside the purpose of this article to describe the cruelties which are inseparable from sport, and from the killing of animals for food, and from See also:fashion; neither is this the place to describe the millions of mutilations which are practised on domestic animals by farmers and breeders. As one of the Royal Commissioners recently said, the farmyards, at certain times of the year, simply " seethe with vivisection." The number of animals wounded in sport, or in traps, cannot be guessed. Against this, vast amount of suffering we have to put an estimate of the condition of 86,277 animals used for medical See also:science. Ninety-five per cent. of them were used for inoculation. In many of these inoculations the result was negative: the animal did not take any disease, and thus did not suffer any pain. In many more, e.g. cancer in mice, tubercle in guinea-pigs, the pain or discomfort, if any, may fairly be called trivial or inconsiderable. It could hardly be said that these small animals suffer much more than an equal number of the same kind of animals kept in little cages to amuse See also:children. There remain 3888 animals which were submitted to operation under an anaesthetic . In the greater number of these cases the animal was killed then and there under the anaesthetic, without recovering consciousness. In the remaining cases the animal was allowed to recover, and to be kept for observation; but no further observation of any kind, which could cause pain, was allowed to be made on it, unless it were again placed under an anaesthetic. Many of these cases, thus allowed to recover after an operation, may fairly be compared to an equal number of domestic animals after one of the formal operations of veterinary surgery. These observations made under Certificate B form but a very small proportion of the total number of experiments on animals in the United Kingdom; and they have led, in See also:recent years; to discoveries of the very utmost importance for human life and health. II. SCIENTIFIC RESULTS.—We come now to consider the results of experiments on animals, but we must remember that not we alone, but animals also, owe a great See also:debt to them. Great epizootic diseases like See also:anthrax, See also:swine-See also:fever, chicken See also:cholera, silkworm disease, pleuro-See also:pneumonia, See also:glanders, See also:Texas See also:cattle fever, blackleg, See also:tuberculosis in cattle, have killed yearly millions of animals, and have been brought under better control by these experiments. The advantages that have been obtained for man may be arranged under two heads—(A) :Physiology, (B) Pathology, Bacteriology and See also:Therapeutics. A. PHYSIOLOGY 1. The Blood.—See also:Galen (A.D. 131) confuted the See also:doctrine of Erasistratus, that the arteries contained ,rv€Gµa, the breath of life, proving by experiment that they contain blood. " Ourselves, having tied the exposed arteries above and below, opened them, and showed that they were indeed full of blood." Realdus See also:Columbus (1559), though he did not discover the general or " systematic " circulation of the blood, yet seems to have discovered, by experiment, the pulmonary circulation. " The blood is carried through the pulmonary artery to the See also:lung, and there is attenuated; thence, mixed with air, it is carried through the pulmonary vein to the left See also:side of the See also:heart. Which thing no man hitherto has noted or left on record, though it is most worthy of the observance of all men.... And this is as true as truth itself; for if you will look not only in the dead body but also in the living animal, you will always find this pulmonary vein full of blood, which assuredly it would not be if it were designed only for air and vapours... . Verily I pray you, 0 candid reader, studious of authority, but more studious of truth, to make experiment on animals. You will find the pulmonary vein full of blood, not air or uligo, as these men call it, See also:God help them." Harvey's See also:treatise De Motu Cordis et Sanguinis in Animalibus was published at See also:Frankfort in 1621. It begins thus: " When by many dissections of living animals, as they came to See also:hand,—Cum multis vivorum dissectionibus, uti ad manum dabantur, —I first gave myself to observing how I might discover, with my own eyes, and not from books and the writings of other men, the use and purpose of the movement of the heart in animals, forthwith I found the matter hard indeed and full of difficulty; so that I began to think, with Frascatorius, that the movement of. the heart was known to God alone. . . . At last, having daily used greater disquisition and See also:diligence, by frequent examination of many and various living animals—multa frequenter et See also:varia animalia viva introspiciendo—I came to believe that I had succeeded, and had escaped and got out of this See also:labyrinth, and therewith had discovered what I desired, the movement and use of the heart and the arteries. And from that time, not only to my See also:friends but also in public in my anatomical lectures, after the manner of the See also:Academy, I did not fear to set forth my opinion in this matter." Here, and again at the end of the See also:Preface, and again in the eighth See also:chapter of the De Motu, he puts his experiments in the very foreground of the See also:argument. Take the headings of his first four chapters: 1. Causae, quibus ad scribendum auctor permotus fuerit. 2. Ex vivorum dissectione, qualis fit cordis motus. 3. Arteriarum motus qualis, ex vivorum dissectione. 4. Moms cordis et auricularum qualis, ex vivorum dissectione. He had, of course, help from other See also:sources—from See also:anatomy and from physics; but it is certain, from his own words, that he attributed his See also:discovery, in a very great measure, to experiments on animals. See also:Malpighi (1661), professor of See also:medicine at See also:Bologna, by examining with a See also:microscope the lung and the mesentery of the live See also:frog, made out the capillary vessels. He writes to See also:Borelli, professor of See also:mathematics at See also:Pisa, that he has failed in every See also:attempt to discover them by injecting fluids into the larger vessels, but has succeeded by examining the tissues with the microscope: " Such is the divarication of these little vessels coming off from the vein and the artery, that the See also:order in which a See also:vessel ramifies is no longer preserved, but it looks like a network See also:woven from the offshoots of both vessels " (De Pulmonibus, 1661). See also:Stephen See also:Hales (1733), See also:rector of Farringdon and See also:minister of See also:Teddington, and a See also:Fellow of the Royal Society, made the first exact estimates of the blood pressure, the real force of the blood, by inserting one end of a See also:vertical See also:glass See also:tube into the crural artery of a See also:mare, and noting the rise of the blood in the tube (Statical Essays, containing Haemostaticks, &c., 1733). See also: These facts were fresh in his mind when he first ventured, in See also:December 1785, to tie the femoral artery in " Hunter's See also:canal " for the cure of aneurism in the popliteal space. The experiment that gave him his knowledge of the collateral circulation was made on one of the See also:deer in See also:Richmond See also:Park: he tied its See also:external See also:carotid artery, to see what effect would be produced on the shedding of the antler. Some days later he found that the circulation had returned in the antler. He had the See also:buck killed, and found that the artery had been completely closed by the ligature, but the small branches coining from it, between the heart and the ligature, were enlarged and were in communication with others of its branches beyond the ligature; and bye this Collateral circulation the flow of blood to the antler had en restored. Among later observations on the circulation must be mentioned the use of the See also:mercurial See also:manometer by Poiseuille (1828) and See also:Ludwig (1849), the study of the blood pressure within the heart by Hering (1849) and the permanent tracing of the pressure curves by Chauveau and Marey (1863). Finally came the study of those more abstruse problems of the circulation that the older physiologists had left alone—the influences of the central nervous system, the relations between blood pressure and secretion, the See also:automatism of the heart-See also:beat, and the influence of See also:gravitation. Professor Starling, in 1906, writes as follows of this part of physiology: " Among the researches of the last thirty years, those bearing on the circulation of the blood must take an important place, both for their physiological See also:interest and for the weighty influence they have exerted on our knowledge and treatment of disorders of the vascular system, such as heart
disease. We have learned to measure accurately the work done by the great heart-See also:pump; and by studying the manner in which this work is affected by different conditions, we are enabled to in-crease or diminish it, according to the needs of the organ. Experiments in what is often regarded as the most transcendental See also:department of physiology—i.e. that which treats of muscle and nerve—have thrown See also:light on the wonderful See also:process of ` See also:compensation ' by which a diseased heart is able to keep up a normal circulation." And Dr See also: 2. The Lacteals.—Asellius (1622) by a single experiment demonstrated the flow of chyle along the lacteals. The existence of these See also:minute vessels had been known even to Galen and Erastistratus, but they had made nothing of their knowledge. Asellius says: "I observed that the nerves of the intestines were quite distinct from these See also: Thus the theory of digestion entered a new phase: it was finally recognized, at least for certain substances, that digestion is not simply dissolution, but a true chemical transformation " (Claude Bernard, Physiologie opiratoire, 1879). Beaumont's experiments on Alexis St Martin (vide supra) were published in 1838. They were, of course, based on the work of the physiologists: " I make no claim to originality in my opinions as respects the existence and operation of the gastric juice. My experiments confirm the doctrines (with some modifications) taught by Spallanzani and many of the most enlightened physiological writers " (Beaumont's preface to his See also:book). Eberle, in 1834, showed how this knowledge of the gastric juice might be turned to a practical use, by extracting it from the mucous membrane of the stomachs of animals after death: hence came the invention of the various preparations of See also:pepsin. Later, Blondlot of See also:Nancy, in 1842, studied the gastric juice by the method of a fistula, like that of St Martin. More recent observations have been made on the movements of the stomach during digestion, and on the influences of the nervous system on the process. The stomach is, of course not the only organ of digestion: the See also:liver, the See also:pancreas and the intestinal glands, all are concerned. The recent work of Pawlow and of Starling has greatly advanced our knowledge of the actions of the secretions from these organs. The whole See also:chain of processes, nervous and chemical, psychical and See also:physical, from the taking of food into the mouth to the See also:expulsion of the See also:waste See also:residue, is now viewed in its entirety; and especial study has been given to the influences, nervous or chemical, which are exercised, as it were, on a particular tract of the See also:digestive system, at the bidding of another tract. Pawlow, recognizing the importance of keeping the animals under the most normal conditions that were possible, and of studying the different tracts of the digestive system in animals not anaesthetized, yet See also:free from pain or See also:distress, made use of fistulae established at different points of the digestive canal, and was able to study the digestive juices at different stages during digestion, without causing pain to the animals. The work of Pawlow has been further See also:developed by Professor Starling's recent work on the chemical substances produced in the body, during the act of digestion, to promote digestion. 4. Glycogen.—Claude Bernard's work on the assimilation and destruction of See also:sugar in the body was begun in 1843. His discovery of the glycogenic action of the liver was made by keeping two dogs on different diets, one with sugar, the other without it, then killing them during digestion, and testing the blood in the veins coming from the liver: " What was my surprise when I found a considerable quantity of sugar in the hepatic veins of the dog that had been fed on meat only, and had been kept for eight days without sugar ! Finally, after many attempts—apres beaucoup d'essais et flusieurs illusions que je fus oblige de rectifier See also:par See also:des tdtonnementssucceeded in showing, that in dogs fed on meat the blood passing through the portal vein (from the stomach) does not contain sugar before it reaches the liver; but when it leaves the liver and comes by the hepatic veins into the inferior vena cava, this same blood contains a .;onsiderable quantity of a sugary substance (glucose) " (Nouvelle fonction du foie, See also:Paris, 1853). 5. The Pancreas.—The 17th century was a time of very fanciful theories about the pancreas (Lindanus, See also:Wharton, Bartholini), which need not be recalled here. But Sylvius (See also:Francois de Bois) had the See also:wisdom to see that the pancreas must be estimated, not according to its position, but according to its structure, as of the nature of the salivary glands. He urged his See also:pupil, See also:Regnier de Graaf, to study it by experiment, and de Graaf says: " I put my hand to the work; and though many times I despaired of success, yet at last, by the blessing of God on my work and prayers, in the year 1662 I discovered a way of See also:collecting the pancreatic juice." By the method of a fistula he collected and studied the secretion of the pancreas; and by further experiment he refuted Bartholini's theory that the pancreas was a sort of See also:appanage or " biliary vesicle " of the spleen. But he got no help from the See also:chemistry of his time; he could no more discover the amylolytic action of the pancreatic secretion than See also:Galvani could discover wireless telegraphy. Still, he did good work; and Claude Bernard, 18o years later, went back to de Graaf's method of the fistula. His observations, begun in 1846, received a prize from the French Academy in 185o. Sir See also:Michael See also:Foster says of them: " Valentin, it is true, had in 1844 not only inferred that the pancreatic juice had an action on starch, but confirmed his view by actual experiment with the juice expressed from the gland; and Eberle had suggested that the juice had some action on See also:fat; but Bernard at one stroke made clear its threefold action. He showed that it on the one hand emulsified, and on the other hand split up into fatty acids and glycerine, the neutral fats; he clearly proved that it had a powerful action on starch, converting it into sugar; and lastly, he laid bare its remarkable action on proteid matters." At a later date it was discovered that the pancreas, beside its work in digestion, has an " internal secretion ": that it, like the thyroid gland and the suprarenal capsules, See also:helps to keep the See also:balance of the general chemistry of the whole body. Professor Schafer, writing in 1894, says on this subject: " It was discovered a few years ago by von Mering and Minkowski that if, instead of merely diverting its secretion, the pancreas is bodily removed, the metabolic processes of the organism, and especially the See also:metabolism of See also:carbo-hydrates, are entirely deranged, the result being the See also:production of permanent See also:diabetes. But if even a very small part of the gland is left within the body, the carbo-See also:hydrate metabolism remains unaltered, and there is no diabetes. The small portion of the organ which has been allowed to remain (and which need not even be left in its proper place, but may be trans-planted under the skin or elsewhere) is sufficient, by the exchanges which go on between it and the blood generally, to prevent those serious consequences to the See also:composition of the blood, and the general constitution of the body, which result from the complete removal of this organ." This fact, that complete removal of the pancreas, in a cat or a dog, may cause fatal diabetes, is of importance, because the pancreas in some cases of diabetes in man is diseased: but, at present, experiments on animals have not led to any certain or specific cure of diabetes in man. 6. The Growth of See also:Bone.—The experiments made by du Hamel (1739-1843) on the growth of bone by See also:deposit from the periosteum (the thin membrane ensheathing each bone) See also:rose out of Belchier's observation (1735) that the bones take up the stain of See also:madder mixed with the food. Du Hamel studied the whole subject very carefully, and discovered this bone-producing power of the periosteum, which is an important fact in all operations on the bones. As he puts it, in the See also:title of one of his own See also:memoirs, See also:Les os croissent en grosseur par l'addition de couches osseuses qui tirent leur origine :du ptrioste, comme le See also:corps' ligneux des Arbres augmente en grosseur par l'addition de couches ligneuses qui se foment dans l'tcorce. Byfeeding pigs at one time with dyed food, at another with undyed food, he obtained their bones in concentric layers alternately stained and unstained. His facts were confirmed by Bazan (1746) and Boehmer (1751); but his conclusions, unfortunately, were opposed by See also:Haller. Still, he brought men to study the whole subject of the growth of bones, in length as well as in thickness, and the whole modellin of the bones, in adult life, by deposit and absorption. See also:Bichat, John Hunter, Troja and See also:Cruveilhier took up his work in physiology and in surgery. Later, from the point of view of surgery, See also:Syme (1837) and See also:Stanley (1849) made experiments on the growth of bone, and on the exfoliation of dead bone; and, after them, Oilier, whose influence on this part of surgical practice has been of the very highest value.
7. The Nervous System. A. The Nerve-Roots.—Through all the centuries between Galen, who lived in the time of See also:Commodus, and Sir See also: Sir John See also:Erichsen says of it: " Up to the time that Sir Charles Bell made his experiments on the nerves of the See also:face, it was the See also:common See also:custom of surgeons to See also:divide the facial nerve for the relief of See also:neuralgia, See also:tic douleureux; whereas it exercises, and was proved by Sir Charles Bell to exercise, no influence over sensation, and its division consequently for the relief of pain was a useless operation."
B. Reflex Action.—The observations made by Sir See also:Robert See also:Boyle, Redi, Le Gallois and others on the reflex movements of decapitated vipers, frogs, eels and butterflies were of no great use from the point of view of physiology; but they led toward the discovery that nerve-power is stored in the spinal cord, and is liberated thence in action See also:independent of the higher cerebral centres. See also:Marshall See also: The Vaso-Motor Nerves.—Claude Bernard, studying the sympathetic nervous system, discovered the vaso-motor nerves that
control the calibre of the arteries. The question of priority between him and See also: E. Cerebral Localization.—The study of the motor and sensory centres of the cerebral hemispheres began in clinical observation. Observation of cases, and examination of the brain after death (Bouillard, 1825, Dax,. 1836, See also:Broca, 1861), led men to believe that a particular area of the left frontal See also:lobe of the brain did indeed govern and permit the use of speech. Physiological experiments had nothing to do with the discovery of the speech centres. " Bouillard in 1825 collected a series of cases to show that the See also:faculty of speech resided in the frontal lobes. In 1861 his views were brought by Aubertin before the notice of the Anthropological Society of Paris. Broca, who was present at the See also:meeting, had a patient under his care who had been aphasic for twenty-one years, and who was in an almost moribund state. The See also:autopsy proved of great interest, as it was found that the See also:lesion was confined to the left side of the brain, and to what we now call the third frontal convolution. . . . In a subsequent series of fifteen typical cases examined, it was found that the lesion had destroyed, among other parts, the posterior part of the third frontal in fourteen " (See also: It would be hard to find a more striking instance of the See also:familiar truth that science and practice work hand in hand. Again, the experimental method has thrown a See also:flood of light on the minute anatomy of the central nervous system. For example, we have what is called Marchi's method; it was described to the Royal Commission (1906-8) by Dr Head and Sir See also:Victor Horsley. It was found, by Professor Waller, that nerve-See also:fibres, separated from the nerve-cells which nourish them, degenerate in a definite way. The application of this law experimentally has been of great value. Let me," says Dr Head, " just take a simile. Imagine a See also:wall covered with creepers arising from several stems. If we wished to know from which of these stems any one See also:branch takes its origin, we could cut one See also:stem, and every See also:leaf arising from it would die, marking out among the healthy foliage the offshoots of the divided stem. This is the principle that has been used in tracing the paths in the nervous system. owers, by applying this method, discovered the ascending tracts in the lateral columns of the spinal cord." If a microscopic section of a spinal cord, containing some fibres thus degenerate, be treated with osmic See also:acid (Marchi's method), the degenerate fibres show dark: and in this way their course may be traced at all levels of the cord. Indeed, it may truly be said that, alike in anatomy and in physiology, the whole present knowledge of the brain, the spinal cord and the nerves, is in great measure due to the use of experiments on animals. And this knowledge is daily applied to the diagnosis and treatment of diseases and injuries of the central nervous system. " In the case of operations on the brain, you have to form your opinion as to what is going on entirely from your knowledge of the physiology of the brain: and that we owe, of course, in the greatest measure to the discoveries of Hitzig and Fritsch and Ferrier. That has all happened since 187o; and we are now able to cure epilepsy, we are able to cure abscess of the brain, and we are able to cure tumours of the brain. Then, in operations on the spinal cord, the same thing prevails. In fact, the first operation on the spinal cord I am responsible for, so that I know the See also:history of the subject. The technique of that operation I owe entirely to experiments on animals. As regards operations on the peripheral nerves, Bell's operative treatment of neuralgia was guided entirely by his experiments on animals. Then we. come to the great subject of nerve suture. The initial work bearing upon that subject was carried out by Flourens, who was the first, to my knowledge, to make experiments on animals, to suture nerves together, to investigate their function " (Sir Victor Horsley, evidence before the Royal Commission, vol. iv. p. I24)., [These notes cover a part only of the results that have been obtained in physiology by the help of experiments on animals. The work of Boyle, Hunter, See also:Lavoisier, Despretz, See also:Regnault and See also:Haldane, on animal heat and on respiration; of See also:Petit, See also:Dupuy, Breschet and See also:Reid, on the sympathetic system; of Galvani, See also:Volta, Haller, du Bois-Reymond and Pfluger, on See also:muscular contraction—all these subjects have been left out, and many more. In his evidence before the Royal Commission (1875), Mr See also:Darwin said: " I am fully convinced that physiology can progress only by the aid of experiments on living animals. I cannot think of any one step which has been made in physiology without that aid."] B. PATHOLOGY, BACTERIOLOGY AND THERAPEUTICS 1. Inflammation.—Pathology is so intimately associated with the work of the microscope, that it is a new study, in comparison with physiology. In 1850 the microscope was not in general use as it Is now; nor did men have the lenses, microtomes and staining fluids that are essential to See also:modern See also:histology. Bacteriology, again, is even younger than pathology. In 1875 ,it had hardly begun to exist. For example, in the evidence before the Royal Commission (1875) one of the witnesses said that they " believed they were beginning to get an idea of the nature of tubercle." Anthrax was the first disease studied by the methods of bacteriology; and in his evidence concerning this disease, Sir John See also:Simon speaks of bacteriology as of a discovery wholly new and unexplored. Then, in 1881, came See also:Koch's discovery of the bacillus of tubercle. But a great advance was made, in days before 1875, by the more general use of the microscope. Every change in the tissues during inflammation—the slowing of the blood stream in the capillary vessels, the escape of the leucocytes through their walls into the surrounding tissues, the stagnation of the blood in the affected part—all these were observed in such transparent structures as the See also:web or the mesentery of the frog, the See also:bat's wing, or the See also:tadpole's tail, irritated by a drop of acid, or a crystal of See also:salt, or a scratch with a needle. It was in the course of observations of this kind that Wharton See also: Suppuration and Wound-Infection.—Practically every case of suppuration, wound-infection or " blood-poisoning," all abscesses, boils, carbuncles, and all cases of puerperal fever, septicaemia, or pyaemia, are due to infection, either from without or from within the body, by various forms of micro-organisms. The same is true of every case of See also:erysipelas, or cellulitis, or acute See also:gangrene—in See also:short, of the whole multitude of " septic " diseases. The work done on these micro-cocci, and on other pathogenic micro-organisms, involved the study of the phases, antagonisms and preferences of each kind, their range of variation and of virulence, their products, and the influences on them of air, light, heat and chemical agents. The beginning of Lister's work was in Pasteur's study of the souring of milk, about 1856. Pasteur's discovery, that lactic See also:fermentation was due to a special micro-organism, opened the way for modern surgery. Lister had been long studying the chemical changes in decomposing blood and other animal fluids; now he brought these studies into See also:line with Pasteur's work. Thus, in T867, In his first published writing on the antiseptic treatment of See also:compound fractures, he speaks as follows: " We find that a flood of light has been thrown upon this most important subject by the philosophic writing of M. Pasteur, who has demonstrated, by thoroughly convincing evidence, that it is not to its See also:oxygen, or to any of its gaseous constituents, that the air owes this See also:property (of producing decomposition), but to minute particles suspended in it, which are the germs of various See also:low forms of life long since revealed by the microscope, and regarded as merely accidental concomitants of putrescence; but now shown by Pasteur to be its essential cause." The present antiseptic method includes the aseptic method. That is to say, the instruments and other accessories of an operation are " sterilized " by heat; and, where heat cannot be applied, as to the patient's skin and the surgeon's hands, antiseptics are used. Modern surgery is both antiseptic and aseptic. 3. Anthrax.-The bacillus of anthrax (charbon, See also:malignant pustule, wool-sorter's disease) was the first specific micro-organism discovered. Rayer and Davaine (185o) observed the petits bdtonnets in the blood of See also:sheep dead of the disease; and in 1863, when Pasteur's observations on lactic-acid fermentation were published, Davaine recognized that the bdtonnets were not blood crystals, but living organisms. Koch afterward succeeded in cultivating the bacillus, and in reproducing the disease in animals by inoculation from these cultures. Pasteur's discovery of preventive inoculation of animals against the disease was communicated to the Academie des Sciences in See also:February 1881; and in May of that year he gave his public demonstration at Pouilly-le-Fort. Two months later, at the See also:International Medical See also:Congress in London, he spoke as follows of this discovery: " . La methode que je viens de See also:vous exposer pour obtenir des vaccins du charbon etait a See also:peine connue qu'elle passait dans la grande pratique pour prevenir 1'See also:affection charbonneuse. La See also:France perd chaque annee pour une valeur de plus de vingt millions d'animaux frappes du charbon, plus de 30 millions, m'a dit une des personnes a.utorisees de notre Ministere de l'See also:Agriculture; mais des statistiques exactes See also:font encore defaut. On me demanda de mettre a 1'epreuveles resultats qui precedent par une grande experience publique, a Pouilly-le-Fort, pres de See also:Melun. . . Je la resume en quelques mots; 50 moutons furent mis a ma disposition, nous en vaccinames 25, les 25 autres ne subirent aucun traitement. Quinze jours apres environ, les 5o moutons furent inocules par le microbe charbonneux le plus virulent. Les 25 vaccines resisterent; les 25 non-vaccines moururent, tous charbonneux, en cinquante heures. Depuis tors, dans mon laboratoire, on ne peut plus suffire a preparer assez de vaccin pour les demandes des fermiers. En quinze jours, nous avons vaccine clans les departements voisins de Paris pres de 20,000 moutons et un See also:grand nombre de bceufs, de vaches et de chevaux." The extent of this preventive vaccination may be judged from the fact that a single institute, the Sero-Therapeutic Institute of See also:Milan, in a single year (1897-98) sent out 165,000 tubes of anti-charbon vaccine, enough to inoculate 33,734 cattle and 98,792 sheep. In France, during the years 1882-93, more than three million sheep and nearly half a million cattle were inoculated. In the Annales de l'Inslitut Pasteur, March 1894, M. Chamberland published the results of these twelve years in a See also:paper entitled " Resultats pratiques des vaccinations contre le charbon et le rouget en France." The mortality from charbon, before vaccination, was 10 % among sheep and 5% among cattle, according to estimates made by veterinary surgeons all over the country. With vaccination, the whole loss of sheep was about 1%; the See also:average for the twelve years was 0.94. The loss of vaccinated cattle was still less; for the twelve years it was 0.34, or about one-third %. The See also:annual reports sent to M. Chamber-See also:land by the veterinary surgeons represent not more than half of the work. " A certain number of veterinary surgeons neglect to send their reports at the end of the year. The number of reports that come to us even tends to become less each year. The fact is, that many veterinary surgeons who perform vaccinations every year content themselves with writing, 'The results are always very good ; it is useless to send you reports that are always the same.' We have every See also:reason to believe, as a matter of fact, that those who send no reports are satisfied; for if anything goes wrong with the herds, they do not fail to let us know it at once by special letters." The following tables, from M. Chamberland's paper, give the results of Pasteur's treatment against charbon during 1882-93, and against rouget (swine-See also:measles) during 1886-92. It is to be noted that the mortality from rouget among swine, in years before vaccination, was much higher than that from charbon among sheep and cattle: " It was about 20%; a certain number of reports speak of losses of 6o and even 8o%; so that almost all the veterinary surgeons are loud in their praises of the new vaccination." It would be too much to say that every country, in every year, has obtained results with this anthrax-vaccine equal to those which have been obtained in France. Nor would it be reasonable to See also:advocate the compulsory or wholesale use of the vaccine in the British Islands, where anthrax is rare. For the general value of the vaccine, however, we have this striking fact, that the use of it has steadily increased year by year. A See also:note from the Pasteur Institute, dated November29, 1909, says: Depuis 1882 jusqu'au Janvier 1909, 'I a ete expedie, pour la France, 8,400,000 doses de vaccin anti-charbonneux pour moutons, 1,300,000 pour bceufs. Pour 1'etranger, 8,5oo,000 doses pour moutons, 6,200,000 pour bceufs. Le nombre de doses augmente d'annee en annee, de sorte que pour I'annee 1908 seule it faut compter en tout 1,500,000 doses pour moutons (France et etranger) 1,100,000 pour bceufs." (Two doses are used for each animal.) It remains to be added that a serum-treatment, introduced by Sctavo, has been found of considerable -'alue in cases of anthrax (malignant pustule) occurring in man. 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