13     I do not mean that sort of experience of which the ordinary practitioners of the old school boast, after they have for years worked away with a lot of complex prescriptions on a number of diseases which they never carefully investigated, but which, faithful to the tenents of their school, they considered as already described in works of systematic pathology, and dreamed that they could detect in them some imaginary morbific matter, or ascribed to them some other hypothetical internal abnormality. They always saw something in them, but knew not what it was they saw, and they got results, from the complex forces acting on an unknown object, that no human being but only a God could have unravelled—results from which nothing can be learned, no experience gained. Fifty years' experience of this sort is like fifty years of looking into a kaleidoscope filled with unknown colored objects, and perpetually turning round; thousands of ever-changing figures and no accounting for them!