352 THE AMERICAN MONTHLY [Oct. 



blue and partly violet). There especially does not exist 

 any transition from red to violet, but rather a marked 

 contrast made by both colors ; never can a strong-over- 

 stained violet connective tissue cell be confounded with a 

 red nucleated mast-cell. Above all there comes in here, 

 in order to bring out this ideal staining of mast-cells, 

 certain methods of bleaching which I will only indicate 

 as I have thoroughly described them in my article on the 

 staining of the protoplasm of connective tissue cells, 

 namely : the decolorization by means of (1) glycerine- 

 ether mixture and (2) neutral alcoholic orcein solution. 



These have the particular advantage over the methods 

 heretofore used, in that they coini^ide with the demonstra- 

 tion of the protoplasm (1 and 2) and collagen (2) in the 

 tissues. We therefore use no other staining solution or 

 method of staining, for in this way we always get the 

 mast-cells stained in a most beautiful and precise manner 

 when the necessary staining is made in regard to proto- 

 plasm and collagen. Naturally, these methods of de- 

 colorizing are not the only ones which are practiced on 

 such sections as have been over-stained by means of 

 the polycrome methylene blue soluticui. All acids and 

 most salts cause the mast-cells, after treatment with 

 alcohol, to appear more or less red, and the number of 

 such methods is legion. But whoever desires to save 

 time, and material will prefer this method above all 

 others, as it brings out so many valuable details 

 and requires so little time. 



Yet, there are some cases in which a specific staining, 

 according to the original method of Ehrlich, deserves the 

 preference. There are certain cases in which we are 

 concerned less with the examination of individual mast- 

 cells than with the finding of all isolated mast-cell nuclei, 

 whether it be that these, as in the different dermatoses 

 (carcinoma, urticaria, pigmentosa) have entered into the 



