Very many animals show parasitic infestation at postmortem, but the percentage in which they can be said to be principal causes of death is quite small, while that in which they play a rôle as activator of the terminal condition is also small but indeterminate. The latter group comprise, together with the anemias mentioned above, certain forms of pneumonia, of hepatic and vascular lesions. Inflammations of the lungs from ascaris and paragonimus are fairly well known; fortunately we have been troubled less with this than have most gardens, possibly because we do not have such large herds of herbivora susceptible to it. Hepatic diseases from flukes, from coccidia and from amœbæ we have always with us in small numbers, but they are unimportant excepting enterohepatitis, a condition which appears in nearly all orders. This last disease, be it purely amœbic as in dysentery of man and monkeys, or like blackhead of turkeys and chickens or in the forms of quail disease, arrests the attention at once and evokes a desire to explain the association of large intestines and liver. Parasitic vascular lesions are relatively unimportant. Taking parasitic infestations by and large, there are close similarities throughout the entire animal kingdom, and the effects produced by a given genus will be repeated almost exactly in several others. The pathological pictures of anemia, of hepatic degeneration, of cystic degeneration, of colonic ulceration or of fibroses are similar in different hosts, only slight variations in the type of inflammation being noted, for instance in reptiles and birds as against the mammals. We have made rather close observations upon the effect of parasites in the production of neoplasms, incited by Fibiger’s discovery of nematodes in the rat’s stomach cancer, but, with the possible exception of a papillomatous growth in the stomach of opossums from the action (?) of physaloptera, we have been unable to establish such an etiological relationship. A decision of the importance of parasites in any given case is not without its difficulty, and we are inclined to reserve judgment pending further analysis unless the effect of the invaders is unequivocal. Leiper[4] does not seem to credit animal parasites with a great effect on the mortality after a specimen has been in the collection six months since all the intestinal varieties he studied came from animals dying in that period. On the other hand the forms which invaded the internal organs and tissues were, in his series, from specimens resident several years in the garden. He seems to think the conditions of life at the garden favor the expulsion of intestinal worms. To what extent some intestinal worms may be commensal remains as uncertain as the value of certain bacteria in the gut tract. In man considerable importance has been ascribed to certain fermentative and putrefactive germs in the maintenance of a reaction unfavorable to