Pathology is the science of disease in all its manifestations, whether structural or functional, progressive or regressive.
It is when studied on these lines that pathology finds its proper place as a department of biology.
This subject brings the domain of pathology, however, into touch with that of variation, and we are profoundly ignorant as to the complex of external conditions which would decide in any given case how far a variation in form would be prejudicial or otherwise to the continued existence of a species.
While thus rejecting all the lessons of morbid anatomy and pathology, he put forward views respecting the causes of disease which hardly bear to be seriously stated.
Hippocrates had no opportunity of verification by necropsy, and Sydenham ignored pathology; yet the clinical features of many but recently described diseases, such, for example, as that named after Graves, and myxoedema, both associated with perversions of the thyroid gland, lay as open to the eye of physicians in the past as to our own.