and Laboratory Methods. 1867 



r NEWS AND NOTES. J 



The Staining of Mast Cells* — Dr. Goldhorn has made some observations 

 on the staining of mast cells and gives three methods by which these elements 

 may be clearly demonstrated. 



1. Saturate wood alcohol with dahlia or methylen blue and pour the solution 

 on a freshly made blood smear without previous fixation. The preparation is 

 then washed in water for a few seconds and dried in air. 



2. The second method is one devised by the author, and considered by him 

 the most simple in manipulation and universal in application to the various ele- 

 ments of normal and pathological blood of any stain yet offered to blood work- 

 ers. With it erythrocytes stain pink, eosinophile granules more or less red, 

 nuclei of leucocytes from blue to purple, and granules of mast cells most promi- 

 nently metachromatic. The malaria parasite is stained as by Plehn's solution, 

 but the nucleus of the young form is well seen. The nuclei of parasites in ani- 

 mal blood are brought out most beautifully. Blood platelets stain also. 



The stain used in this method is prepared as follows : Methylen blue is 

 rendered polychrome as directed on page 1635 of this Journal and is then made 

 strongly acid with glacial acetic acid. Next add 5 per cent, eosin solution till 

 the mixture is transformed into a pulpy mass. Filter through two layers of filter 

 paper and dry the mass left on the paper in a hot-air oven, after which it is dis- 

 solved in wood alcohol. If the solution when thus prepared is too acid, stain- 

 ing erythrocytes too deeply and leucocytes very little or not at all, the desired 

 reaction may be obtained by rendering wood alcohol alkaline with potassium 

 carbonate and adding it gradually until the dye gives the desired results. If the 

 stain is made strictly neutral or alkaline, the red corpuscles will take on a green- 

 ish hue and the granules and anaemic degenerations will be shown while they 

 will not be seen when the dye is acid. To use the stain it is only necessary to 

 flood the slide for a few seconds and wash in. water. Over-staining with a neutral 

 stain is impossible. Eosinophile granules are seen by allowing the stain to act 

 for about fifteen seconds. The strength of the stain may be altered by varying 

 the amount of alcohol. 



3. Another most satisfactory method is the following : Saturate wood alcohol 

 with methylen blue and immerse the blood smear in this for about fifteen sec- 

 onds. Wash in water and stain in .1 per cent, aqueous eosin for from fifteen to 

 thirty seconds. If the smear is simply dipped into the eosin solution and the 

 lower side of the slide wiped off so that a thin film of eosin is left on the upper 

 side, the staining of the different granules may be observed under a medium 

 power of the microscope; after the desired result is obtained wash and dry in air. 

 The nuclei of leucocytes may be TDrought out more clearly if the smear is dipped 

 in weak polychrome methylen blue before drying. To use the stain for mast 



*L. B. Goldhorn. Bull. Med. Sci. 2 : 2. 



