THE STAINING OF BACTERIA IN TISSUES. 109 



Cover-glasses on whicli substances rich in albu- 

 minous matter are placed, should be examined at 

 once. If they are put to one side for only a few days 

 even, the acetic acid has no longer the power of 

 dissolving part of their plasma, and in consequence, 

 the difference of colour between the tissue and the 

 bacteria is less marked. 



