180 ANIMAL PAEASITES. 



has not had a too abundant supply of nourishment. In the 

 human subject it has not yet been found, and, indeed, there can 

 very rarely be an opportunity for a man to acquire this Tcenia, as 

 its scolex from its size attracts the attention of the butcher, so 

 that it is cut out, thrown away, and swallowed by the expectant 

 dogs. An experiment made with Cystic, tenuicollis on the mur- 

 derer referred to under T. solium gave no certain result, and it 

 must remain for futurity to determine whether this T&nia thrives 

 in the human intestine or not. Dr. Moller, also, who swallowed 

 several Cysticerci tenuicollis, di^l not acquire any Teenies ex Cyst, 

 tenuicolli. I have often bred it in the intestine of the dog ; it 

 becomes mature in 10 14 weeks. It is as well, in the artificial 

 administration of the cystic worm to dogs ; to cut the caudal 

 vesicle, as uninjured vesicles are easily vomited by dogs. More- 

 over, this cutting is the most in accordance with nature, as, 

 when the butcher throws such a Cysticercus to a dog, the latter 

 chews and injures it before swallowing it, which is not the case 

 when we push the cystic worm down the throat of the dog. 



The six-hooked embryos live enclosed in eggs of 0-039 

 millim. = 0-0176'" in length and the same in breadth. 



The capsules of these eggs have a much lighter colour than 

 those of the other large-hooked Tcenia of the dog, and they are 

 smoother on their outer surface. The embryos themselves pre- 

 sent the well-known six embryonal booklets pretty distinctly ; 

 these are of the following size : 0-003 millim. = O'OOl'" in length, 

 the embryo being 0-02.2 millim. = 0-004'". 



That these eggs must be at some time or other in the human 

 intestine, and that the embryos must be found for a time 

 free in the human body, is a matter of course ; but our means are 

 not sufficient to discover the migrating embryos with our present 

 instruments. 



The scolex state of this Tcenia forms the Cysticercus tenui- 

 coins, which, having been frequently seen in man by the earlier 

 authors, was mentioned by them as Cystic, visceral, hominis ; l 

 but having become more rare in modern times, or at least 

 amongst us and the civilised nations of Europe, has therefore 

 been entirely struck out by modern authors, or placed amongst 



1 In domestic animals the Cysticercus tenuicollis was known (vid. sup.} to Hartmann 

 and Tyson : Peyer, in 1689, also described it, but only as a hydatid, and it was known to 

 Bartholin (1653), Steno, and Harder. 



