130 



TH^ MICROSCOPE. 



Sept. 



A marked difference from all the other members of this 

 family will be noticed here in the form of the fore-legs. 

 These lack the heavy claws of the other pairs, and have, 

 instead, a slender tapering form with a very slightly 

 curved tarsal nail. The effect is to give them more ready 

 means of moving over flat surfaces, and of turning over 

 if thrown upon the back." — Riverside Natural History. 



XVII. — Cyst of Trichina Spiralis. 



This figure is also drawn from a photograph kindly 

 sent us by Dr. Borden. The trichina is a worm which 

 buries itself in the muscles of hogs, sheep, etc. When 



the flesh of an infested animal is eaten, the encysted 

 worm is dissolved out by the gastric juices and then pro- 

 gress is rapid. In a week millions of eggs are produced 

 and soon hatched. The young then penetrate the walls 

 of the intestine and set up a severe irritation throughout 

 the body causing intense suffering. If the patient can 

 get through the few weeks of suffering, the trichinae 

 will in turn become encysted and cease to do harm. 



In 1884, the flesh from one pig killed and eaten in 

 Saxony, Germany was tasted by 361 persons who took 

 the malady and 57 of them died within four weeks. 



