164 THE AMERICAN MONTHLY [May 



but in alcohol it gives a blue solution with strong- green 

 fluorescence. It is more soluble in methyl alcohol. Dr. 

 Jenner in the Clinical Laboratory of St. Thomas' Hospital, 

 London, has adopted this solution for fixing and staining 

 blood. He makes it of equal parts of a half per cent to one 

 and a quarter per cent solution of Grubler's water-soluble 

 eosin, yellow shade, in distilled water and of a one per cent 

 solution of Grubler's medicinal methylene blue also dis- 

 tilled in water. These are mixed together in an open basin 

 (not in a flask) and thoroughly stirred with a glass rod. 

 Preferably, let the mixture stand 24 hours, filter, dry the 

 residue either in the air or in an oven. It can be dried at 

 55 degrees C. without harm. When dry, scrape off the 

 residue from the filter paper and powder it. Shake this up 

 with distilled water and wash in a filter. The washing will 

 be of a thin dirty-purplish color. Again dry, powder and 

 store in bottles. When wanted for use, shake up one-half 

 a gramme of the powder with 100 cubic centimeters of 

 pure methyl alcohol and filter. This stain may be equally 

 well made by dissolving the eosin and the medical methy- 

 lene blue directly in absolute methylic alcohol and mixing 

 them in proportion of 125 cc.of .5 per cent solution of eosin 

 with 100 cc. of .5 per cent solution of methylene blue. Or 

 prepared solution may be purchased from R. Kanthack, 

 18 Berners Street W. London, or from American dealers. 

 This stain is a single solution, easily made, keeps well, 

 will fix and stain blood films in two minutes. It will de- 

 monstrate, with perfect clearness, with rapidity, certainty, 

 and in well marked contrasts the red blood discs, the blood 

 platelets, the nuclei of white blood cells, the fine granules 

 of the polymorpho nuclear leucocytes, the coarse oxyphil 

 granules, the basophil granules, and when present ery- 

 throblasts, bacteria, malarial parasites and filariae. It is 

 a simpler and clearer method than any heretofore publish- 

 ed. The differential staining results from the decompo- 

 sition of the compound substance by the various elements 

 of the blood, those parts which are acid combining with 

 the basic coloring matter and those that are basic combin- 

 ing- with the acid part. That the stain is readily so split up 



