2042 Journal of Applied Microscopy 



green, thionin, etc., are called basic stains; those in whith a staining acid 

 is combined with an inert base, as eosin, orange G., aurentia, acid fuchsin, etc., 

 are called acid stains. To these two general classes of stains Ehrlich has added 

 a third, which are especially important in the staining of blood. Stains of this 

 class are produced by adding a solution of a basic dye in proper proportion to 

 a solution of an acid dye. A precipitate results which is believed to consist of 

 the staining base of the basic dye united with the staining acid of the acid dye. 

 This compound dye is called by Ehrlich a neutral stain. 



Of the elements of the blood, the nuclei, the granules of certain of the leuco- 

 cytes (mast cells), the cytoplasm of the lymphocytes, the cytoplasm of the imma- 

 ture red corpuscles before hemoglobin development, and malarial parasites and 

 bacteria when present, have a varying affinity for the first class of stains, the 

 basic stains, and, following the generally accepted terminology, may be called 

 basophile. The discoplasm of mature red corpuscles, the granules of certain 

 leucocytes (acidophiles) and the cytoplasm of the leucocytes have a vary- 

 ing affinity for the second class of stains, the acid stains, and may be called 

 acidophile. The neutral stains, being a compound of basic and acid dyes, 

 stain both basophile and acidophile elements and in addition stain the 

 granules of a third variety of leucocytes in human blood which are not stained 

 by either the basic or the acid stains, and which are called neutrophik. 



A. Basic Stains. 



1. Dahlia. 



Ehrlich'' s staining fluid for the granules of the mast cells consists of : 

 Absolute alcohol, - - - - 50 c. c. 



Distilled water, . . - - 100 c. c. 



Glacial acetic acid, . - - - 12.5 c. c. 

 Dahlia to thorough saturation. 

 The preparations should be floated on the surface of this staining solution 

 for twenty-four hours, and then washed and examined either in water or dried 

 and mounted in balsam. All of the basophile elements of the blood are stained, 

 including the granules of the mast cells which are not stained by many of the 

 basic dyes. 



Goldhorn (1902) recommends wood alcohol saturated with dahlia for 

 staining mast cells. The staining solution is poured on the fresh blood smear 

 without previous fixation. The preparation is then washed with water and dried 

 in the air. 



2. Dahlia and Carmin. 



Westphal (1880), who worked under Ehrlich, used the following dahlia mix- 

 ture : 100 c. c. Carmin of Partsch-Grenacher (pure carmin 2.0, distilled water 

 200.0, alum 5.0 ; cooked one-fourth hour, filtered and 1.0 carbolic acid added), 

 100 c. c. of glycerin, 100 c. c. of strong alcoholic solution of dahlia, 20 c. c. of 

 acetic acid. 



3. Haematoxylin. 



Afannaherg recommends the following alum haematoxylin solution for 

 staining malarial blood : A fairly old solution of 10 grains of cryst. haematoxylin 



