302 BACTERIOLOGY 



and stain for two to three minutes. Ehrlich's acid luema- 

 toxyliiie, which has been much used for staining coccidia, is 

 prepared by adding 6 parts of glycerine and 60 of water, 

 both saturated with alum, and 3 parts of glacial acetic acid, 

 to a solution of 2 parts hsematoxyline in 60 parts absolute 

 alcohol. Filter, stain for 3 to 5 minutes. 



Eosine is used as a double stain in a T V per cent, aqueous 

 solution in which the sections, after being stained in hgema- 

 toxyline and washed, are immersed for one or two minutes. 



Picro-carmme is made by dissolving 1 grin, carmine in 

 5 grms. strong ammonia and 50 grms. water, and adding 50 

 grms. of saturated aqueous solution of picric acid, after 

 which the stain is left standing in a wide open vessel until 

 all the ammonia has evaporated, and is then filtered. Stain 

 for an hour, soak for half an hour in glycerine containing 

 1 per cent, of hydrochloric acid and coloured light yellow 

 with picric acid, wash for five minutes in water, and de- 

 hydrate in alcohol, both of which are similarly tinted. 



Alum carmine solution is made by boiling 2 to 5 grms. 

 carmine with 100 grms. 5 per cent, alum solution for a half 

 to one hour, and filtering. Stain for ten minutes to two 

 hours. 



Nicolle claims to have discovered a method of fixing the 

 colour of bacteria, useful for those which bleach under 

 Gram's process : The sections are stained for two or three 

 minutes in Loffler's or Kiihne's methyl blue, slightly 

 decolorised in feebly acid water, washed, dipped for an 

 instant in 10 per cent, tannin solution, washed in water, 

 dehydrated, cleared in oil of cloves, and mounted in xylol 

 Canada balsam. 



