MICROSCOPICAL DIAGNOSIS. 



43 



from moving farther. In the hog, fragments of muscle should 

 be examined especially from the ham and tenderloin. They are 

 usually found arranged spirally just beneath the sarcolemma. 

 This spiral arrangement gives them their specific name, trichina 

 spiralis. They were discovered in January, 1860, by Professor 

 Zenker of Dresden. In 1864 Professor Dalton counted the 

 number of trichinae in a piece of muscle T 1 of an inch square and 

 -f 1} - of an inch thick, and found 12. This would give about 85,000 

 to the cubic inch. In another specimen of the same size he 

 found 29 trichina;, giving again in round numbers 208,000 to 



Ftg. 12. 



A, fatty infiltration of heart (man), x 75. B, fatty degeneration of muscle from arm 

 of boy, amputated on account of paralysis of three years standing. 



the cubic inch. The trichina? in half a pound of infested meat 

 would be sufficient in a few days to develop the extraordinary 

 number of 30,000,000. When it is remembered that each of 

 these worms must puncture the mucous membrane in its way to 

 the muscles, it is readily understood why they should occasion 

 such notable disturbance. As found in muscles they are usually 

 surrounded by a cyst containing granules or calcareous matter. 

 In size they average about --$ of an inch in length and -g-^, of 

 an inch in thickness. They retain their vitality in the encysted 

 state for a great length of time. 



Muscle sometimes becomes streaked with fat when it can 



