2] 2 ENTOZOA. 



the earliest times, though possibly not earlier than the measles, 

 from which the worm originates. Hippocrates, Pliny, and Aris- 

 totle described the fiiU-grown worm ; and, in regard to the larvae, 

 some have gone so far as to express their belief that the prohibition 

 of swine's flesh as food amongst the Jews and other Oriental people, 

 was dictated by sanitary considerations. Weinland suggests that 

 the Mosaic commandment not to eat pork might have originated in 

 an old popular notion " of the fact that tapeworm sometimes comes 

 from this food." Certainly, one must admit the possibility of the 

 truth of Weinland' s hypothesis ; for, if one supposes Moses to have 

 been supernaturally informed that (measly) pork would produce 

 tapeworm disease among the people, one naturally asks why veal 

 and beef should not also have been prohibited, seeing that these 

 meats also harbour tapeworm larv^, nearly as frequently as pork. 



Anatomy. — Now that the general organization and mode of 

 development of this species is so well understood, it is a matter of 

 regret that the manifest errors of earlier writers are not more care- 

 fully excluded from our ordinary manuals of zoology and compara- 

 tive anatomy. I allude, for example, to such points as the stUl 

 asserted presence of a mouth and digestive canal in the Tcenia, 

 which cannot be maintained, since repeated demonstrations have 

 clearly proved this view to be erroneous. These falsely so-called 

 alimentary canals constitute the water-vascular system which will 

 be briefly described below. I say " briefly," because the hmits and 

 design of this work will not permit me to give excessively minute 

 anatomical details. 



The head of Taenia soliwm is seldom seen in our pubhc anato- 

 mical museums, although the evacuation of entire adult tapeworms 

 is not of very rare occurrence. Placed under the microscope, it 

 displays, in addition to the characters already mentioned, a quan- 

 tity of dark, almost black, pigment granules, which are particularly 

 abundant at the base of the rostellum, and in the neighbourhood 

 of the hook sacs. They exhibit a bright crystalline aspect, and 

 vary somewhat in quahty ; this proportion, however, being neither 



