CHAPTER VIII. 



THE STAINING OP BACTERIA IN HUMAN AND ANIMAL 

 TISSTIES. 



In order to demonstrate bacteria in animal tissues, it 

 is necessary to cut the thinnest possible sections of 

 them. This cannot, however, be done without some- 

 what complicated preparations being made beforehand, 

 as the tissue itself is too soft and gives way too much 

 to the razor in cutting. The best substance for hard- 

 ening the animal tissues, which are to be used for bac- 

 teriological purposes, is absolute alcohol, which we 

 shall settle to make use of once for all in all such 

 work. 



We will suppose that the spleen of a patient who 

 has died of typhoid has been made over to us from 

 some hospital for examination; this is a material which 

 is generally obtained without much difficulty. The 

 fresher the spleen, the better ; if it has begun to de- 

 compose, it is no longer any good for this purpose. 

 We cut the spleen up into small pieces about a cubic 

 centimetre in size, and place them into a fairly large 

 quantity of absolute alcohol. After about two hours 



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