224 ANIMAL PARASITES AND MESSMATES. 



the natural size. Fig. 1 represents an isolated and 

 magnified seolex ; A, shows the segments of the future 

 proglottides ; D, the suckers ; C, the hooks ; H, the 

 vesicle which contains them. 



Eggs of the same taenia have been given to sheep at 

 Copenhagen and at Giessen, and Messrs. Eschricht and 

 E. Leuckart have obtained the same result as we had at 

 Louvain. On the fifteenth or sixteenth day. the first 

 symptoms of " gid " declared themselves. At about the 

 thirty-eighth day the crown of hooks appeared, the 

 suckers were formed, and the whole head of the seolex 

 was sketched out. All these heads can leave or enter the 

 sheath at the will of the animal. It is truly a poly- 

 cephalous animal when the scolices are expanded. This 

 worm continues to grow for a long time in the cranial 

 cavity, and produces by its presence the gravest results. 

 The sheep necessarily dies at last, unless we remove 

 the parasite by means of the trepan. 



The ccenurus, at this point of development, swallowed 

 by a dog, undergoes great changes in a few hours. The 

 proscolex, or large vesicle, withers ; the different scolices 

 unsheath their cephalic extremity, become free, penetrate 

 into the intestine with the food, and attach themselves to 

 its walls, so as to form as many colonies of taenia as there 

 are distinct heads. A dog which has swallowed a single 

 ccenurus may therefore contain a considerable number of 

 taeniae. 



The development of this worm proceeds very rapidly, 

 and it only requires three or four weeks to attain many 

 feet in length. The organization of this worm, in the 

 state of strobila and of proglottis, is in every respect like 

 that of the Taenia serrata ; we have even endeavoured in 



