THE STAINING OF BACTERIA IN TISSUES. 103 



OTIS aniline dyes, and may be kept in well closed 

 bottles for years in a condition fit for use. 



The sections, if sufficiently .thin, need only remain 

 in tbis Loffler's metbylene blue for from five to ten 



Pig. 7. 



minutes; thicker sections must be left in for a longer 

 time, even in some cases for an hour. If aqueous 

 solutions are used, tbe sections must sometimes be left 

 in for more than twenty-four hours, before they are 

 sufficiently stained. When this has been accomplished, 



