TRANSMIGRATIONS AND METAMORPHOSES. 



223 



develops itself on the brain of tlie sheep, and occasions 

 the disease known by the name of "gid." This disease 

 may be produced artificially. The sheep which swallows 

 the eggs of this taenia shows the first symptoms of it 

 towards the seventeenth day. If we kill it at this time, 

 we find on the surface of the brain, either at the base or 

 the summit, or sometimes between the hemispheres and 

 the cerebellum, one or more white vesicles of the size of 

 a pea, and on which no traces of buds are yet to be seen. 

 This vesicle, of a milky-w^hite colour, and filled with 

 liquid, is the scolex. Near these vesicles are to be seen 

 some very irregular yellow furrows, like tubes abandoned 

 by some tubicolar annelid ; this is the gallery through 

 which the vesicular worm has proceeded to the place 

 where it has been found. 



A fortnight later, that is 

 to say, about the thirty- 

 second day, the coenurus is 

 as large as a small nut, and 

 one can see with the naked 

 eye some small nebulous cor- 

 puscles, separate fi'om each 

 other, of the same form and 

 size; these are the buds or 

 scolices which have risen 

 up, but which, as yet, have 

 neither hooks nor suckers. 



We give the representa- 

 tion of one of these vesicles, 

 on the internal walls of which 

 young scolices have been developed ; this is nearly of the 

 natural size. Fig. 2, a, a, shows these scolices of .nearly 



Fig. 54.— CcEuurusof the sheep. 1, the 

 enclosed scolex ; 2, Hydatic vesicle, 

 with the scolices in their place within 

 it. 



