ANIMAL PARASITES. 



123 



The female trichinella is a fine thread-like worm 

 measuring from 3 to 4 millimeters long; the male is 

 smaller, measuring 1.5 millimeters, and has two little 

 appendages from the hinder end (bifid). 



Practically all domestic 



animals may act as host 

 for the trichinella, but in- 

 festment in man is seldom 

 due to any other meat be- 

 sides pork. The disease 

 occurs wherever pork is 

 eaten. In suspected cases 

 the worms should be 

 sought in the stools, or 

 embryos may be obtained 

 by removing a small frag- 

 ment of the pectoral or 

 biceps muscle under local 

 anaesthesia. 



If pork or other meats 

 are suspected of contain- 



FiG. 9. — Trichinella spiralis. En- 

 capsulated larva in muscle. (Tyson 



ing tnchinella, the latter ^ft^^^raun.) 

 may be easily demonstrated by treating a thin section of 

 the tissue with a solution of caustic potash (i-io) and 

 viewing it with the low-power lens of a microscope. 



Should the specimen be very fat, treat it with ether 

 or dilute acetic acid first and then with the caustic 

 potash solution. 



