S54 THE AMERICAIT MONTHLY [Oct. 



nuclei by subsequent decolorization is accomplished all 

 collagenous tissue and protoplasm are bleached, only the 

 nuclei retain somewhat more of the blue than by the 

 alum method. On the other hand, the red nuclei stand 

 out so plainly that one cannot miss them even with a 

 low power. 



In the following list I give the methods in use in my 

 laboratory for staining with i)oly chrome methylene blue: 



I. 



Metachromatic Staining of Mast-Cells, especially in 

 connection loith Plasma Cells and Protoplasm. 



(a) 1. Stain in polychrome methylene blue solution 

 (Grruebler) from one-quarter hour to one night. 



2. Decolorize in a mixture of a few drops of glycerine- 

 ether solution in a saucer of water. 



3. Thorough washing in water. 



4. Absolute alcohol, oil of bergamot, and balsam. 



(b) 1. Stain in polychrome methylene blue solution 

 for from five to fifteen minutes. 



2. Wash in water. 



3. Decolorize and wash in one-quarter per cent of 

 alcoholic neutral solution of orceiu (Gruebler) about one- 

 quarter hour. 



4. Absolute alcohol, oil, balsam. 



II. 



Isolated Metachromatic Staining of Mast-Cells in very 

 Weakly- Stained Tissue. 



(a) 1. Staining in polychrome methylene blue solu- 

 tion with a knife point of alum in a saucer of coloring 

 solution three hours to one night. 



2. Wash in water. 



3. Decolorize in glycerine-ether solution for from five 

 to ten minutes. 



4. Prolonged washing in water. 



5. Absolute alcohol, oil and balsam. — St. Louis Medi- 

 cal and Surgical Jouriial. 



