ENTOZOA IN THE NERVOUS SYSTEM. 193 



whole extent of the cerebro- spinal axis. The 

 hydatids will be first described, and the cysticerci 

 subsequently. 



The cyst, or pouch, of hydatids developed in the 

 brain is single in the majority of cases. Its bulk, 

 which is very variable, may equal that of a hen's egg, 

 or it may even exceed that size ; in a case, observed 

 by Headuigton, recorded in the " Edinburgh Medical 

 and 'Surgical Journal" (vol. xv, page 504), the pouch 

 contained a pound of fluid, and in another case, 

 which came under the notice of Rendtorf, a mass of 

 hydatids, weighing two and a half pounds, was found 

 within the pouch. The hydatid pouch in the brain 

 encloses, similarly to cysts in other organs, sometimes 

 only one large hydatid, and sometimes a great number 

 of these bodies, of variable dimensions. 



When the pouches which enclose the hydatids are 

 multiple, the patient necessarily perishes before they 

 have acquired any considerable size. In illustration 

 of this fact, a very interesting case, described by 

 Calmeil, Physician to the Lunatic Asylum at Charen- 

 ton, may be quoted ; it is that of an officer in the 

 army, who, until within a short time before his 

 admission, was in possession of perfect health ; in 

 the course of a few months, the patient died, his 

 intellectual faculties, and sensory and motor func- 

 tions having been successively lost ; when a post- 

 mortem examination was made, almost innumerable 

 small acephalocysts were found scattered upon the 

 surface, and in the iuterior, of the brain. 



The hydatid pouch in the brain is formed, as far 

 as may be judged from the observations which have 

 been made, by a depression of the cerebral substance, 



o 



