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Scientific Proceedings (131) 



suggested to me by Mr. Chambers : Coverslips were flooded 

 with an aqueous solution of the dye, which was allowed to 

 evaporate, leaving the dry dye evenly distributed on the cover- 

 slip. The drop of blood was placed on this coverslip and studied 

 as a hanging drop, suspended in culture slides. The observa- 

 tions were made in a warm chamber. 



Out of a dozen various dyes I have found the two following 

 to be the best. They are both American made dyes. Janus 

 Green from the Providence Chemical Laboratories and 

 Cresylecht Violet from the National Aniline and Chemical Co. 

 This American Janus Green is taken up very rapidly. During 

 the first few seconds it colors the cytoplasm diffusely and 

 gradually concentrates on the granules, which finally take up all 

 of the stain, leaving the cytoplasm almost transparent. The 

 eosinophil granules are very prominent and large and take a 

 deep blue color. During this time the cell exhibits amoeboid 

 movements. The granules move but seldom entend into the 

 slender pseudopodia. 



After one hour, as the cell begins to die, the Janus Green tends 

 to fade out of the granules and enters the hitherto colorless 

 nucleus, coloring it violet. This is significant because it indi- 

 cates a reduction of the dye. The neutrophil leucocytes have 

 very fine granules which stain more faintly. These granules 

 exhibit greater activity of movement than those of the 

 cosinophiles. In dead cells, both eosinophil and neutrophil, the nu- 

 cleus loses its color while the granules again take up the stain and 

 persist as deeply stained granules for a long time. 



Cresylecht Violet is more toxic than Janus Green. Its pre- 

 liminary effect, however, is to stimulate not only the cells but 

 also the cytoplasmic granules to considerable activitiy. 



In the neutrophil cells I have found two distinct kinds of 

 granules, first, one which is apparently identical with that of 

 the eosinophil and second, one which is very small. The large 

 granules may be few or many. Although these granules re- 

 semble the eosinophil granules, we cannot consider them as 

 being the same, because, during the decoloration of the cell 

 which accompanies its death these large granules fade out at 

 the same time and in the same way, as the fine neutrophil 

 granules and, therefore, earlier than the granules of the 

 eosinophil cell. 



