See also:

• ANATOMY
• ANATOMY (Gr. avaroyil, from ava-silo c', to cut up)

Here, also, the path by which such messengers travel is the blood stream. A further and most important manner in which the circulating fluid is utilized in the life of an See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

It is while passing through the capillaries that the blood performs its See also:

• WORK

On the course of the lymphatics a number of typical structures, the lymphatic glands, are placed, and the See also:

• LYMPH

(2) It may produce chemical substances which act as poisons to the micro-organism, either paralysing it or actually killing it. Or (3) the organism may be attacked and taken up into the body of wandering cells, e.g. certain of the leucocytes, and then digested by them. Such cells are therefore called phagocytes (4aryecv, to eat). Thus, by itspower of reacting in these ways the body has become capable of withstanding the attacks of many different varieties of micro-organisms, of both animal and See also:

• VEGETABLE

The main waste products dissolved in it are ammonium carbonate, See also:

• UREA, or CARBAMIDE, CO(NH2)2

It possesses the typical properties of a globulin, i.e. it coagulates on See also:

• HEATING

When blood clots two new proteins make their See also:

• APPEARANCE (from Lat. apparere, to appear)

To some extent it varies in composition with that of the fat absorbed, but usually consists of the glycerides of the See also:

• COMMON

The phosphate is present to about 0.02%. Sulphuric acid is always present if the blood has been calcined for the purposes of the See also:

• ANALYSIS (Gr. avci and Meta, to break up into parts)

With rare exceptions their shape is that of a biconcave disk with bevelled edges, the size varying somewhat in different animals, as is seen in the following table which gives their diameters: Man 0.•0075 mm. See also:

• DOG

1,000,000 to 4,000,000 See also:

• FISH (O. Eng. fist, a word common to Teutonic languages, cf. Dutch visch, Ger. Fisch, Goth. fisks, cognate with the Lat. piscis)
• FISH, HAMILTON (1808-1893)

The amount present, though small bears a perfectly definite quantitative relation to the amount of oxygen with which the haemoglobin is capable of combining (two atoms of oxygen to one of iron). One See also:

• GRAM

The amount of bile pigment eliminated during the See also:

• DAY (O. Eng. dreg, Ger. Tag; according to the New English Dictionary, " in no way related to the Lat. dies")
• DAY, JOHN (1574-1640?)
• DAY, THOMAS (1748-1789)

The Polymorphonuclear Cell.—This possesses a nucleus of very complicated outline and a See also:

• FAIR

4. The Hyaline (Gr. vaAcuos, glassy, crystalline, &\m, See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

The lymphocytes are derived from lymphoid tissue, wherever it exists in the different parts of the body. The polymorphonuclear and eosinophile cells are derived from the bone-marrow, each by See also:

• DIVISION (from Lat. dividere, to break up into parts, separate)

See also:

• VARIATIONS
• VARIATIONS, CALCULUS
• VARIATIONS, CALCULUS OF

Since the haemoglobin is practically the same from whatever animal it is obtained and can only combine with the same amount of oxygen, the oxygen-capacity of the blood of any vertebrate is in direct proportion to the amount of haemoglobin it contains. Therefore we see that as we ascend the scale in the vertebrate See also:

• SERIES (a Latin word from serere, to join)

Birds' blood is stated to contain no platelets. The variations in number of these bodies have not been satisfactorily ascertained on See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

For example, human blood kept at body temperature clots in three minutes, while if allowed to cool to See also:

• ROOM

Soon after their deposition they begin to See also:

• CONTRACT
• CONTRACT (Lat. contract us, from contrahere, to draw together, to bind)

It is to prevent, as far as possible, any loss of blood when there is an injury to an animal's vessels. The shed blood becomes converted into a solid, and this, extending into the interior of the ruptured vessel, forms a plug and thus arrests the bleeding. It is found that clotting is especially accelerated whenever the blood touches a foreign tissue, for instance, the See also:

• OUTER

The possibilities are, that thrombin may act—(r) by acting upon fibrinogen, which it in some way converts into fibrin, (2) by uniting with fibrinogen to form fibrin, or (3) by yielding part of itself to the fibrinogen which thus becomes converted into fibrin. The experimental study of the rate of fibrin formation, when different strengths of thrombin solutions are allowed to act upon a fibrinogen solution, leads us to the probable conclusion that the first of these three possibilities is the correct one, and that thrombin therefore exerts a true ferment action upon fibrinogen. It is known that in the reaction, in addition to the formation of fibrin, yet another protein makes its appearance. This is known as fibrinoglobulin, and apparently it arises from the fibrinogen, so that the change would be one of cleavage into fibrin and fibrinoglobulin. It is very noteworthy that although the amount of fibrin formed during the clotting appears very bulky, yet the actual See also:

• WEIGHT

In the study of this question it has been found that if the blood of birds be collected direct from an artery through a perfectly clean cannula into a clean and dust-free glass vessel, it does not clot spontaneously. The plasma collected from such blood is found to contain thrombogen but no thrombokinase. A some-what similar plasma may be prepared from a mammal's blood by See also:

• COLLECTING

When blood escapes from a blood-vessel it comes into contact with a foreign surface, either a tissue or the damaged walls of the cut vessel. Very speedily this contact results in the discharge of thrombogen and thrombokinase, the former from the white blood corpuscles and also possibly from the platelets, the latter from the plateletsor from the tissue with which the blood comes in contact. The interaction of these two bodies next results in the formation of prothrombin, which, combining with the calcium of any soluble See also:

• LIME
• LIME (O. Eng. lim, Lat. limes, mud, from linere, to smear)

Secondly, the body has been found to possess the power of making a substance, antithrombin, which can combine with thrombin forming a substance which is quite inactive as far as clotting is concerned. Finally, there is See also:

• EVIDENCE (Lat. evidentia, evideri, to appear clearly)

Doses of organisms or their toxins can be injected on one or several occasions, and provided that the lethal dose be not reached, in most cases an increased power of resistance is produced. The organisms may be injected alive in a virulent condition, or with their virulence lessened by See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

The antiserum produced in the case of the red corpuscles may sometimes, if injected into the first animal, whose red corpuscles were used, cause extensive destruction of its red corpuscles, with haemoglobinuria, and sometimes a fatal result. Opsonic action depends on the presence of a substance, the " opsonin," in the serum of an immunized animal, which makes the organism in question more easily taken up by the phagocytes (leucocytes) of the blood. The opsonin becomes fixed to the organisms. It is present to a certain extent in normal serum, but can be greatly increased by the process of immunization; and the " opsonic index," or relation between the number of organisms taken up by leucocytes when treated with the serum of a healthy See also:

• PERSON, OFFENCES AGAINST THE

The chemistry of the blood has not hitherto been found to give See also:

• INFORMATION (from Lat. informare, to give shape or form to, to represent, describe)

Anaemia is often used as a generic See also:

• TERM

The diagnosis depends ultimately in all cases upon the examination of the blood. Though the relative proportions of the leucocytes are probably continually undergoing change even in See also:

• HEALTH

This compensatory change is found in all chronic anaemias, no matter what their cause may be, except in some rare cases in which the marrow does not react. It is often very difficult, especially in " secondary " anaemias, to say which of the above processes is mainly at work. In acute anaemias, such as those associated with septicaemia, there is no doubt that blood destruction plays the See also:

• PRINCIPAL

Chlorosis is the type of anaemias from imperfect blood-formation. Lorrain Smith has produced evidence to show that the total amount of haemoglobin in the body is not diminished in this disease, but that the blood-plasma is greatly increased in amount, so that the haemoglobin is diluted and the amount in each blood-unit greatly lessened. Pernicious anaemia is a rarer disease than chlorosis, occurs usually later in life, and is distributed nearly equally between the two sexes. But it is of great importance because of its almost uniformly fatal termination, though its downward courseis generally broken by temporary improvement on one or more occasions. The symptoms are those of a progressive anaemia, in which gastro-intestinal disturbance usually plays a large part, and See also:

• NERVOUS

Not all persons affected with this intestinal tapeworm contract the disease, but only those in whose intestines the See also:

• WORM

cubic millimetre is usually about 7000, but may vary in health from 5000 to 10,000. A diminution in their number is known as leucopenia, and is found in See also:

• STARVATION

In the one form these are lymphocytes, which areibund in health mainly in the marrow, the blood itself, the lymph glands and in the lymphatic tissue See also:

• ROUND (O. Fr. rond, Lat. rotundus, the Fr. is the source also of Du. rond; Ger., Swed., Dan. and Nor. rond)

In certain pathological conditions, however, it brings relief and saves life when no other means would act with sufficient promptness to take its place. Venesection, in which the blood is usually withdrawn from the median-basilic vein of the See also:

• ARM (a common Teutonic word; the Indo-European root is ar, to join or fit; cf. the Lat. armus, shoulder, and the plural word arma, weapons, Gr. apphs, joint, and the reduplicated apapilKSV, to join)

In acute See also:

• LUNG

Such a criminal was outlawed, and his enemies could kill him wherever they found him.