128 



122. Fixing with ether-alcohol. When the blood films 

 on the covers are dry, place them in ether-alcohol (equal parts) for 

 YZ-I or several hours. Let them fix for a longer rather than a 

 shorter time, as the quality of the stain (with triacid mixture) will 

 be improved. After they have fixed a sufficient time remove and 

 again dry them in the air. They may now be stained, immediately 

 or at convenience. 



123. Fixing with heat. Place a gas or alcohol flame under 

 the apex of a triangular copper tabte (or other similar warm table or 

 incubator). When it is well heated determine the region that has 

 a temperature equal to the boiling point of water (100 C) by plac- 

 ing on it drops of water at varying distances from the flame. Just 

 within the point so determined (nearer the flame) place the covers 

 bearing the dried film of blood, film side down upon the copper 

 plate. Leave them for 15-30 minutes or longer. When the covers 

 have cooled they are ready to be stained. 



(<r) Staining with (#) Eosin and Hematoxylin, (b} Hhrlich's 

 'Triacid Mixture, or (c) Methylene Blue. 



124. Eosin and hematoxylin. Stain the fixed blood films 

 for 2-3 minutes with a l / 2 % aqueous solution of eosin, rinse with 

 water and stain for 10-15 minutes with hematoxylin, rinse again 

 with distilled water and allow the film to dry. When dry, warm the 

 cover gently to remove the last traces 'of moisture and mount in 

 balsam. This gives a good general stain of the blood corpuscles, 

 both red and white. Red corpuscles will be stained red or pink, 

 the nuclei of the white corpuscles will be blue, and their cell bodies 

 but faintly stained ; eosinophile granules, a bright pink. 



125. Ehrlich's triacid mixture ( 93). Place a drop or 

 two of the mixture upon the film side of the cover. Stain for 10-15 

 minutes, rinse in distilled water, dry, and mount in balsam. 



If the stain is successful, red corpuscles will be orange-yellow, 

 nuclei of white corpuscles, blue, cell bodies, pale pink, eosinophile 

 granules, copper red. This stain is used a great deal in the clinical 

 examination of blood and is a valuable one. Should the red corpus- 

 cles be colored red instead of orange-yellow, it means that the fixa- 

 tion has fjeen insufficient ; if ether-alcohol was used for fixing, the 

 time was too short ; if heat was employed, the degree of heat was 

 insufficient or the time too short. The right time of fixation and 

 staining: must be, in many cases, determined by experiment. 



