16 TROPICAL MEDICINE AND HYGIENE 



For general blood work Leishman's modification of 

 Romanowsky's stain is the most generally useful. This 

 is the solution in pure methylic alcohol of the precipitate 

 formed when polychrome methyl blue and eosin in 

 watery solutions are mixed. 



Unfixed films must be used. There arc three stages 

 in the process of staining : 



(i) The solution of Leishman's stain is placed on the 

 slide so as to cover the film. This fixes the film and 

 the stain penetrates the corpuscles, but little staining 

 occurs. Time, half to one minute. The solution must 

 not be allowed to dry on the film. 



FIG. 5. 



(2) Distilled water is added to the solution of the stain 

 in methylic alcohol that has been placed on the slide, 

 and the water is rapidly mixed with the solution. The 

 amount should be sufficient to cause an abundant pre- 

 cipitate of the stain and the mixture should appear pink. 

 The water should be about double the amount of the 

 solution used. It is during this stage that staining takes 

 place. Time required, five minutes or more. It is best to 



