138 PARASITES OF MAN 



infests only the dog and the wolf.' Therefore, considering the 

 immense number of pariah dogs fed on the refuse of animals 

 infected with hydatids, it seems more than probable that the 

 parasite must attain its strobila condition in their intestines, and 

 through them be eventually disseminated over the pastures on 

 which the cattle graze." 



I now turn to a neglected phase of the subject from which 

 much practical instruction may be gathered. The consideration 

 of the pathological phenomena of hydatid disease as it affects the 

 lower animals is of high interest, and no prejudice should induce 

 any medical man from accepting such useful data as may be 

 gathered from this source. The facts of hydatid parasitism in 

 animals, though often peculiar, are, for the most part, of an 

 order similar to those presented in the human subject. If any 

 medical practitioner thinks it beneath his dignity to study the 

 pathology of the lower animals, the conduct of John Hunter in 

 this respect is a standing protest against such narrowness. 



The museum of the Royal College of Surgeons of England 

 contains some of the finest specimens of hydatids from the lower 

 animals that are to be seen anywhere, the very choicest of them 

 having been selected by Hunter himself. That distinguished 

 ,man sought information from every available source, and 

 hydatids were for him of almost equal interest, whether found 

 in the body of a human being or in the carcase of an ox or an 

 ass. Now, at all events, neither pathologists nor sanitarians can 

 well afford to neglect comparative pathology ; and, for myself, I 

 am free to say that the yearly exposition to the students of the 

 Eoyal Veterinary College of the phenomena of parasitic life 

 amongst animals has brought with it an ever-increasing know- 

 ledge of the most curious and often unlooked-for information. 

 Some of the data thus supplied are quite remarkable. Let me 

 also add that my studies of the entozoa of wild animals have put 

 me in possession of particulars of high value in regard to 

 the larger question of the origin of epidemics. Beasts, birds, 

 reptiles and fishes, of every description, are liable to succumb 

 to internal parasites, and there is practically no end to the 

 variety of useful information to be obtained from this source. 

 I have collected materials almost sufficient for a separate treatise 

 on this department of the subject, but I fear I shall never have 

 either the time or opportunity to give the facts due publicity. 

 Here, for obvious reasons, I must for the most part restrict 

 myself to the hydatids properly so called. 



