116 A MANUAL OF BACTERIOLOGY 



(6) Eosin (alcohol-soluble and water-soluble) : 



A somewhat diffuse stain. Is used for counter-staining the 

 tissues in Gram's method, and for staining red blood-corpuscles 

 and acidophile granules in leucocytes. 



A | to 1 per cent, aqueous or alcoholic solution may be used, 

 and the staining should not, as a rule, be prolonged for more than 

 about half a minute. 



(7) Bismarck brown (Vesuvin) : 



A saturated aqueous solution should be prepared and diluted 

 somewhat for use. A good counter-stain for the tissues in Gram's 

 method. Stain for two to five minutes. 



(8) Orange-rubin : 



Prepare saturated aqueous solutions of orange G. and rubin S. 

 Mix equal volumes and dilute with water until of a light port-wine 

 colour. Stain tissues for five to fifteen minutes. A good contrast 

 stain for tuberculosis and actinomycosis. 



(9) Picro-carmine : 



This is best bought ready prepared. Sections are stained in 

 the solution for half to one hour, washed, then treated w T ith 

 alcohol acidified with a few drops of hydrochloric acid for two or 

 three minutes, and finally washed in water. The section can 

 now be counter-stained with Loffler's blue or by Gram's method. 



(10) Hsematoxylin : 



Ehrlich's formula is one of the best and simplest to use, and 

 can be obtained ready for use. It must be " ripe." It is a histo- 

 logical and not a bacterial stain. Sections are treated as follows : 



(1) Distilled water, one to two minutes. 



(2) Stain with the haematoxylin solution for five to thirty 

 minutes. In some cases the solution is preferably diluted some- 

 what with distilled water. 



(3) Einse in distilled water. 



(4) Rinse in distilled water containing a trace of acetic acid. 



(5) Treat with distilled water containing a trace of ammonia. 

 The sections remain in this until they assume a deep blue colour. 

 (Tapwater, five to ten minutes, may also be used.) 



