154 Methods of Observing Bacteria 



have been abandoned. The affinity between the bacteria 

 and the anilin dyes is peculiar, and in certain cases can be 

 used for the differentiation of species. 



The best anilin dyes made at the present time, and those 

 which have become the standard for all bacteriologic work, 

 are made in Germany by Dr. Grubler, and in ordering stains 

 the name of this manufacturer should be specified. 



A whole volume 

 could easily be de- 

 voted to the tech- 

 nic of staining. In- 

 deed, the difficul- 

 ties encountered 

 are so great that 

 no explanations 

 can be too thor- 

 ough to be useful. 

 Readers interested 

 in the biochemis- 

 try of the subject 

 will do well to refer 

 to the excellent 

 papers by Arnold 

 Grimme,* upon 

 "The Important 

 Methods of Stain- 

 ing Bacteria, etc.," 

 and Marx,t upon 

 " The Metachro- 

 matic and Babes- 

 Ernst Granules." 



In this work 

 special methods for 

 staining such bac- 

 teria as have pecu- 

 liar reactions will 

 be given together 

 with the descrip- 

 tion of the particular organisms, general methods only 

 being discussed in this chapter. 



*"Centralbl. f. Bakt.," etc., Bd. xxxn, Nos. 2, 3, 4, and 5, 1902. 

 xxxn, Nos. 10 and 11, p. 108, 1902. 



Fig. 21. Apparatus for keeping objects 

 under microscopic examination at constant 

 temperatures (Nuttall). 



