EXAMINATION OF CYSTICEECOID STAGES 



153 



under the cover-glass in alcohol. They are treated with alcohol and 

 glycerine, and finally enclosed in glycerine-gelatine. 



It is a more difficult matter to effect the evagination of the head 

 in the smaller Cysticercoid varieties, such as C. cellulosce of swine, 

 C. boms of cattle, and C. pisiformis of rabbits. 

 But in these more transparent varieties, the head 

 is seen lying within the bladder and may be cut 

 out. It should be pressed between two glass- 

 slides and examined with a low power micros- 

 cope. Good specimens may be converted into 

 either stained or unstained permanent prepara- 

 tions. 



FIG. 73. Longitudinal section through 

 a Cysticercus. (After Leuckart.) 



FIG. 74. Cysticercus 

 pisiformis, with com- 

 pletely evaginated head 

 and body. 18:1. (After 

 Leuckart.) 



In the case of the larger Tsenise, such as T. crassicollis, the 

 rostellum and hooks of which are seen with the naked eye, it is 

 easy to sever the protruded end of the rostellum with a razor, and, 

 after clearing and mounting (glycerine or balsam), to examine it under 

 the microscope. 



The Echinococcus is found in the liver and lungs of animals 

 fattened for slaughter, and is the Cysticercoid stage of the small 

 T. echinococcus, which inhabits the intestine of the dog. The 

 encysted parasite may grow to the size of an apple, though the 

 cysts found in cattle are frequently sterile. In such cases, the bladder- 

 wall is composed only of the cuticular layers and of the delicate 

 germinal layer attached to their inner surface. In fertile Echinococci, 

 the inner surface of the germinal layer shows numerous small, thin- 

 walled bladders ; these are the brood-capsules, from the walls of which 

 numerous scoleces have been derived, and these may be found in 

 all stages of development. These scoleces will be seen if portions 

 of the germinal layer are removed from the cuticle and spread out 

 upon glass-slides, -wherever possible in liquid from the cyst (fig. 76). 

 To fix these, portions of germinal layer should be spread out on a 



