84 



DISEASES OF MUSCLES AND TENDONS. 



Beef measles 

 Switzerland, and 



is rather common in Germany, but rare in France, 

 Italy. 



Trichinosis is 

 Trichina spiralis. 

 undergoes sexual 

 trichinosis, which 

 disease. 



The trichinaB 

 directly deposited 



TRICHINIA.SIS-TRICHINOSIS. 



a disease caused by the entrance into the body of the 



This parasite is swallowed in the larval form, and 



changes in the intestine, at first producing intestinal 



represents the first phase in the development of the 



breed rapidly. The embryos penetrate into or are 

 in the blood-vessels, which convey them to all parts of 



Fig. 44. — Gravid segment of beef- 

 measle tapeworm {Tcenia sagi- 

 nata), showing lateral branches 

 of the uterus, enlarged. (Stiles, 

 Annual Report U.S.A. Bureau 

 of Agriculture, 1901.) 



Fig. 45. — Egg of beef-measle tapeworm 

 {Tcenia saginata), with thick egg-shell 

 (embryophore), containing the six- 

 hooked embryo (oncosphere), enlarged. 

 (After Leuckart.) 



the body, thus setting up the second phase of the disease, known as 

 muscular trichinosis. 



Trichinosis as a disease has long been recognised. Peacock in 1828 

 and J. Hilton in 1832 mentioned the existence of the cysts of trichinsG ; 

 Owen in 1835 gave the name of Trichina spiralis to the parasites con- 

 tained in the cysts. Trichinosis being common in Germany at that time, 

 Virchow and Leuckart undertook its investigation, but mistook other 

 nematodes of the intestine for the Trichina spiralis. In 1847 Leydy 

 recognised that trichinosis occurred in American pigs. 



In 1860 Zenker found muscular and intestinal trichinosis on post- 

 mortem examination of a girl who had been suspected of suffering from 

 typhoid fever, and a carefully conducted inquiry revealed the fact that 



