STAINING, PRACTICAL AND 



C. Solution A 

 Solution B 

 Tap water 

 Propylene glycol 



Note: The stock solutions A and B can each be prepared with 

 only I gm. of the dyes, but in that case it will be necessary to 

 add a few drops of chloroform (which must be renewed from time 

 to time since it evaporates when the solutions have been kept in 

 stock for a few weeks). If these two solutions are made to contain 

 only i%* of the dyes, then solution C will have to be modified 

 as follows : 



Solution A . . . . . . 2 ml. 



Solution B . . . . . , 8 ml. 



Water 40 ml. 



Propylene glycol . . . . 50 ml. 



Technique: 



I. Dilute samples of the blood in white cell pipette and enumer- 

 ate with a counting chamber as usual. 



Results: 



Eosinophils are stained brilliant red against a light red background. 



Notes: 



The authors state that workers, including Swingle (1955), have 

 pointed out the difficulty in the staining of eosinophils of the dog 

 by the methods that are in use for the blood of humans, rats and 

 mice. The method described above was developed during the 

 course of an investigation on the function of the adrenal cortex 

 of the dog when it became necessary to make routine counts of 

 these cells. It is claimed that with the rose Bengal-phloxin mixture 

 more of the eosinophils can be seen, with a lower error of counting 

 than usually given by single stains. 



It is stated that errors in counting eosinophils stained with 

 phloxine B can be reduced if the blood is collected without any 

 anticoagulant such as heparin. 



The original paper should be consulted for further information. 



Reference: Cueto, C. & Brown, J. H. U. (1958). 



* Without the addition of chloroform as a preservative, the weak solutions 

 are liable to attack by air-borne micro-organisms with the destruction of the 

 dyes. This does not occur with solutions containing io% of the dyes. 



394 



