56 METHODS OF MICROSCOPICAL RESEARCH. 



distilled water before being treated by either of 

 these re-agents. 



Make a 1 per cent, solution of nitrate of silver 

 in distilled water, keep it in a bottle carefully 

 covered all over with black paper. This solution 

 is to be further diluted to a -J, a ^, or a J 

 per cent, as required. Nitrate of silver is used 

 to intensify and demonstrate the outlines and 

 features of endothelium and cartilage cells. The 

 cement substance between the cells absorbs the 

 solution all not absorbed must be carefully washed 

 away with distilled water, and the tissue exposed 

 to direct sunlight. Not the slightest taint of the 

 unabsorbed silver solution must be allowed to re- 

 main upon the surface of the tissue, the staining 

 of which would be spoiled by the black oxide 

 granules of decomposed nitrate of silver. The 

 tissues must be treated within a few minutes after 

 death. 



Omentum of rabbit. Kill a rabbit by bleeding. 

 Remove the omentum and wash it in distilled water; 

 place it in a J per cent, solution ten minutes ; wash 

 in ordinary water thoroughly ; place the whole in 

 a saucer containing water, and expose to diffuse 

 daylight till slightly brown. Small pieces may now 

 be stained with logwood and mounted in glycerine 

 or glycerine jelly, and the logwood stain may be 

 dispensed with if desired. 



Septum Cysternce Lymphaticce magnce of a frog. 

 Kill a frog and immediately open the abdomen. 

 Gently push on one side the stomach, bowels, &c., 

 and pour distilled water on the part behind the 

 stomach, when a delicate membrane floats up. 

 Now pour a -J per cent, solution, drop by drop, 

 over this till it becomes milky, and treat as above. 



