Parasites of Musadar and Connective Tissue. 437 



the two ends until the muscle appears transparent. They are 

 now examined under the low power, when the free trichina, the 

 fusiform sarcolemma containing the trichina, or the ovoid cyst, 

 should stand out clearly. It is important to avoid taking adipose 

 tissue or white or yellow fibrous tissue with the section. 



For the higher power (and usually also for smoked or dried 

 ham or pork) it is best to clear up the sections before mounting 

 them. In this case the stripes of muscle are steeped for fifteen 

 minutes in solution of aceticacid (3:100), caustic potash (10:100), 

 or glycerine (50:100), and then, or as soon as they have become 

 transparent, placed on a glass slide, teased out with needles, and 

 pressed under a cover glass, and examined. This must be done 

 systematically piece after piece and covering the whole field in 

 successive zones, the one hand being used to move the object and 

 the other to work the fine adjustment, so that every part may be 

 brought iuto perfect focus in turn. 



The discovery of a large number of calcified trichinous cysts, 

 does not imply that no live trichinae are present. On the con- 

 trary, it furnishes evidence that the pig has been in a locality 

 where trichina exists, and the older invasion implies the probabil- 

 ity of other and more recent ones, so that all such ca,ses may be 

 held as highly suspicious, and should at least be subjected to a 

 most exhaustive scrutiny. Better still, sterilize the carcase by 

 heat. 



Reference has already been made to other parasites which 

 may be mistaken for trichina. If acetic acid is used to clear 

 up the specimen it should be seen that it is free from anguillula. 

 This may be grossly distinguished by the fact that it tapers to 

 both ends, especially the caudal. The larvae of ascarides and 

 strongyli have the cephalic end broad, and taper toward the tail. 

 The filaria of man and dog also taper toward the tail and show 

 a special membraneous caudal prolongation. None of these nema- 

 todes, nor the rhabditis form the characteristic ovoid cysts in the 

 red muscular fibre, and they are not associated with the profu- 

 sion of semi-microscopic intestinal trichinae. The smallest com- 

 mencing cysts of cysticercus cellulosa, or of echinococcus 

 may be found in the connective tissue of the muscles, but they 

 are differentiated by the globular head with its four sucking discs 

 and the rows of hooklets on the rostrum. Psorosperms in the 



