OTjK domesticated animals. 17 



transferred to the paunch of cattle, will assume their 

 definitive adult form and characteristics within the space 

 of a very few days, or even hours. 



In respect to other practical bearings, apart from those 

 already referred to in connection with the developmental 

 history of the amphistomes, I would observe that, as 

 these parasites are constantly overlooked, so also has the 

 probability of their proving injurious to their bovine hosts 

 escaped suspicion. Their general resemblance to the 

 large pedunculated villi of the paunch, amongst which 

 they lie concealed, readily accounts for the little attention 

 hitherto paid to them ; in fact, not one person in twenty 

 would be likely to observe them, unless specially in 

 search of entozoa. It is little to the point to say that 

 it is of no use acquiring a knowledge of these amphis- 

 tomes because veterinarians have never yet diagnosed their 

 presence in the living animal; neither is it so obvious 

 that they cannot give rise to disease, merely because 

 no local pathological indications display themselves 

 within the rumen. Depend upon it, when these paunch- 

 infesting flukes occur in large numbers, the host is more 

 or less inconvenienced, and if the bearer is not a strong 

 beast constitutionally, external symptoms of impoverished 

 health will sooner or later appear. In this way it is that 

 some of the comparatively harmless entozoa become 

 injurious to their bearers, whether bovine or human. 

 Nay more, there may be no obvious external symptoms ; 

 and yet, as remarked in a paper on the grouse disease 

 (The Field, Nov. 9, p. 451), there may be a gradual and 

 insidious undermining of the health, such as I have fre- 

 quently witnessed in human bearers who have come to 

 me complaining of loss of appetite with general depres- 

 sion of the vital powers. 



c 



