CYSTICERCUS CELLULOSE. 119 



and is nearly allied to chitine, but dissolves, when boiled in 

 caustic alkalies, rather more easily than the latter. The addition 

 of iodine produces no reaction of cellulose, although this is not a 

 rare constituent of the envelopes of the lower animals, as, for 

 instance, of the Timicata. The vesicle contains a fluid con- 

 taining albumen, fat, and calcareous matter, upon the pro- 

 duction and nature of which we have already spoken. I will 

 also dwell no further upon the object of this vesicle, which is 

 only the enlarged six-hooked embryonal vesicle, and which at 

 any rate fulfils the double office of a reservoir of nourishment, 

 and a proliferous organ, as I have already spoken at length upon 

 it in my book on the Cestoidea, and also in the general portion 

 of this Manual. Our scolex never lives in the true fattv tissue, 

 but only in the muscles, in the cellular tissue, the brain and its 

 cavities, within and between the membranes of the eye, and in 

 the orbits. In the serous cavities of the body, such as the 

 brain and the orbits, it lives free ; in the other parts of the body 

 it is enclosed in cysts which originate from the host, and the 

 walls of which present the microscopic composition of those parts 

 of the body in the neighbourhood of which the cestode worm 

 has its habitation. 



The above-mentioned characteristic marks, which are presented 

 by the everted head and the short neck, agree exactly with those 

 of Tcenia solium, and we should only have to repeat what we 

 have said as to the head of T. solium, or in the general part 

 upon the greater abundance of calcareous corpuscles in the cystic 

 worms, and the gradual disappearance of these structures during 

 Tsenial life. Only this one circumstance may be mentioned, that 

 during the scolex period the hook-sacs keep in the background, 

 and only become more distinct, and, at the same time, more 

 resistent, at the period when the black pigment is deposited in a 

 larger quantity on the head, and especially round and in the 

 sacs. A figure of the most essential parts, such as is given in 

 PI. Ill, and a comparative measurement of the sucking discs 

 and hooks, which will follow at the close of the section " Ces- 

 toidea," will render the matter more intelligible than the most 

 exact description. But to complete the proof of the identity of 

 Cysticercus cellulosce, we must not only succeed, as above recorded, 

 in converting Cyst, celluloses into Tcenia solium, but reversing the 

 matter, we must also be able to breed Cysticercus celluloses by 



