SEVENTH ANNUAL REPORT. 141 



Thorough cooking kills the cysticercus, rendering it harmless. 

 It has been demonstrated by several experimenters that a tem- 

 perature of from 55°-65° C. (131° Fr.-i49° Fr.) is sufficient to 

 kill the parasite. In some of the German abattoirs, where the 

 carcasses of animals affected with cysticerci are considered fit for 

 food, the meat is cut into suitable pieces and thoroughly sterilized 

 (in large ovens built for this purpose) before being exposed 

 for sale. 



In this country, where the custom is to cook the meat more 

 or less thoroughly before eating it, the chances of an individual 

 becoming infected with taenia are not so great. With the ex- 

 ception of the heart, Cysticercus cellulosa are seldom found in in- 

 ternal organs, while fat tissue is nearly always free from them. 



CYSTICERCUS TENNICOLLIS. 



This hydatid is found in all domestic and wild ruminants, but 

 is probably most commonly met with in sheep and deer. The 

 progenitor of this hydatid. Taenia marginata, inhabits the intes- 

 tines of the dog, fox, and wolf. 



This hydatid is sometimes confounded with the Cysticercus cel- 

 lulosa, but it has a number of characteristic features which differ 

 very materially from those of the latter, for which it should not 

 be mistaken. 



The size of the cyst depends upon its age and situation. If 

 situated upon serous membranes (which is usually the position 

 of this hydatid), lining closed cavities where Httle or no pressure 

 is exerted upon them, they may reach the size of a hen's egg, or 

 even larger. 



In the case of the mule deer, the cysts of which show so well in 

 the photograph, the largest cyst was about the size of a bantam's 

 egg. In this case the cysts were contained in a sac, apparently 

 formed from the peritoneal tissue, and having the appearance of 

 small water bladders, and at the point of attachment there was 

 a constricted portion produced by the weight of the fluid con- 

 tained in the cyst. The outline of the scolex could be distin- 

 guished through the walls of the cyst, but not as plainly as through 

 a cyst containing Cysticercus cellulosa. 



In a series of experiments carried out by Leuchart, he found 

 that cvsts attained the length of .6 to 3.5 m.m. in ten days 



