1889.] 



PUBLIC DOCinVIENT — No. 34. 



117 



contact with the meat. In counting, only the worms em- 

 braced between two lines were considered while the slide 

 was being moved in one direction ; when the end of the slide 

 was reached, the next adjoining space between two lines was 

 observed while the slide was slowly moved in the op- 

 posite direction. In this way the whole slide was accu- 

 rately examined without danger of counting more than once 

 any single specimen of the worm. The meat was of course 

 firmly pressed between the two slides, so as to flatten it and 

 make it transparent ; and a slight pressure* was continued by 

 means of the thumb and finger with which the slide was 

 grasped in moving it back and forth. 



The magnifying power employed was usually thirty or 

 forty-five diameters. In addition to noting the specimens of 

 meat which were infected with trichinic, and also the number 

 (approximately) of worms found in each case, a record was 

 kept of the sex of the hogs on which the examinations were 

 conducted, so that the results show the proportion both of 

 males and females that were found to be trichinous. 



