6 METHODS OF MICEOSCOPICAL RESEARCH. 



Ovaries of the Cow in small pieces should be 

 macerated in very dilute solution to isolate the 

 large, branched, pigmented cells of the Corpora 

 lutea. 



Ammonium Bichromate. 



A 2 per cent, solution made with ordinary 

 water may be employed. 



This solution is preferred by many to the potass 

 salt solution. It is used in the same way. Columnar 

 epithelium may be prepared as permanent speci- 

 mens by placing a piece of fresh intestine of dog, 

 cat, rabbit, &c., in 1 per cent, solution for two 

 days ; then steeping an hour or two in water and 

 scraping off the epithelium and staining. The cells 

 have to be separated with a needle, and may be 

 mounted in Farrant's medium, or in glycerine jelly. 



Chromate of Ammonium. 



A 5 per cent, solution is used. 



If a newt's liver (in small pieces) and pieces of 

 the small intestines be placed in the solution for 

 forty-eight hours, the liver cells and columnar 

 epithelium may be obtained, as in the case above- 

 mentioned. The goblet cells of Klein can be 

 perfectly preserved in glycerine jelly in this way. 

 The mesentery of the newt may be placed in the 

 solution at the same time, and taken out after 

 twenty-four hours. This shows the non-striated 

 muscle fibre beautifully. The isolated gastric 

 glands of a small mammal may be obtained in 

 the same way by placing pieces of the fresh mucous 

 membrane for three days in the solution. The 



