256 Mr Hardy, On the Reaction of certain [Nov. 9, 



(5) On the Reaction of certain Cell-Grannies with Meihylene- 

 Blue. By W. B. Hardy, B.A., Gonville and Caius College. 



[Received Nocember 30, 1891.] 



In 1878, Prof. Ehrlich pointed out the fact that the granule- 

 containing cells of the body, whether found free in the body fluids 

 or elsewhere, could be distinguished from one another by the 

 character of the reaction of their granules with different aniline 

 dyes*. He distinguished five classes of granules characterised by 

 staining with acid, basic, or neutral dyes, or indifferently with acid 

 or basic dyes (amphophil). The present communication deals with 

 a further subdivision of the basophil granules into two groups, 

 characterised by very distinct colour-reactions with the basic dye 

 methylene-blue, the one class of granules staining a deep blue, the 

 other a bright rose. 



The distinction of tint depends, for some reason not at present 

 at all obvious, on illumination with yellow artificial light. Under 

 these circumstances the colour-contrast is one of extraordinary 

 brilliancy. With daylight, or with gaslight after it has been 

 filtered through neutral-tint glass, the rose colour either appears a 

 blue like that shewn by the blue-staining granules, or is dulled to 

 a blue-violet tint. The explanation of this change may be found 

 in the fact that the yellow gaslight is relatively richer in red rays 

 (or poorer in blue rays) than is daylight, or the phenomena may be 

 of a more complex nature. Be this as it may, the abrupt transi- 

 tion from bright rose to bright blue produced by directing the 

 mirror from the gas flame to the window is a striking feature of 

 this colour-reaction. 



The discrimination of basophil granules into rose-staining or 

 blue-staining varieties may depend upon the dichroic nature of 

 methylene-blue. Thin films produced by running a minute quan- 

 tity of a strong solution under a coverslip appear rose with arti- 

 ficial light, while more dilute solutions appear blue. 



Methylene-blue is a salt having the composition of a chloride, 

 the base being a pigment of the aniline series, and it has already 

 been noticed that alkalies produce a rose or reddish modification 

 possibly by decomposing this salt and liberating the pigment-base. 

 This suggests that the rose tint may not be solely a physical 

 phenomenon but may depend upon a chemical action of the 

 granule substance on the dye, or a chemical change produced by 

 the osmosis of the pigment through the cell protoplasm to the 

 granule. 



That the reaction does not depend simply upon the thickness 



* The various papers dealing with this subject have been republished by 

 Br Ehrlich in pamphlet form under the title "Farbenanalytische Untersuchungen 

 zur Histologic und Klinik des Blutes." Berlin, 1891. 



