192 BACTERIOLOGY. 



After a few seconds pass the slip back into a watch- 

 crystal containing the dilute silver bath (0.25-0.5 per 

 cent, solution of silver nitrate in water) and keep it 

 in constant motion until the solution begins to take on 

 a brown or blackish color. Wash in water thoroughly ; 

 dry with blotting-paper, and mount in balsam. 



