C) I- MOUNTING AND PREPARATION OF OBJECTS. 



tilled water. After an immersion of three minutes it 

 is removed from the gold solution and exposed to 

 the light in a little glycerine, until it assumes a 

 violet gray shade. This will take about twelve 

 hours. A % p. c. solution of nitrate of silver may 

 be used in the same way, and is extremely useful 

 for histological work especially the demonstration of 

 the endothelial linings of serous membranes. 



These preparations are finally mounted in gly- 

 cerine, and kept in tlie dark when not under ex- 

 amination. 



The majority of pathological products require to 

 be cut into thin sections, before their examination is 

 possible. For this purpose they are placed while 

 fresh in Muller's fluid, which consists of — 



Bichromate of Potash, 2 parts. 

 Sodium Sulphate, 1 part. 

 Water, 100 parts. 



This should be omitted if the sections require 

 staining with chloride of gold, or nitrate of silver. 



The organ or tissue is cut into sufficiently small 

 pieces, and placed for three hours in a very thick 

 solution of gum. A little alcohol added to the gum 

 prevents putrefaction and allows it to be used for a 

 considerable time. 



The instruments required for section cutting are a 

 razor and a microtome. The razor is set in a strong 

 wooden handle, it should have a good thick back, 

 both sides being hollow ground. 



Rutherford's microtome consists of a brass table, 



