THE LEUCOCYTES IQI 



us information not yielded by either haematoxylin and eosin or the tri- 

 acid, the points of differentiation to be referred to in that which follows 

 is with blood so stained. 



In considering the staining affinities of different parts of the leuko- 

 cytes 1 , it is convenient to divide such into basic ones, acid ones, and thos-e 

 which may be said to be on the border line between these the so-called 

 neutrophilic affinities. 



With Wright's stain we have the eosinophile or oxyphile affinity of 

 the granules of eDsinophiles for acid dyes, in this case eosin. The 

 nuclei and basophile granules have affinities in greater or less degree for 

 basic stains (the blue and the violet shading resulting from methylene 

 blue as modified by poly chroming) . With the granules in the cyto- 

 plasm of the poly morphonucl ears and neutrophilic myelocytes, and to a 

 less extent in the transitional, we have a staining which merges into a 

 yellowish-red on the one extreme and into a lilac on the other. As a 

 standard, neutrophilic granules should be a mean of these extremes. 



Not only by reason of the authority of Ehrlich, but because such a 

 division gives all variations, which can then be combined by one pre- 

 ferring a simpler classification, it would seem proper to divide the nor- 

 mal leukocytes into : 



1. Small Lymphocytes. These are small round cells about the size 

 of a red corpuscle with a large centrally placed, deeply violet staining 

 nucleus and a narrow zone of cytoplasm. This cytoplasm may not be 

 more than a mere crescentic fringe. This is the type of lymphocyte 

 which makes up the greater proportion of the leukocytes in chronic 

 lymphatic leukaemia. At times these cells seem to be composed of 

 nucleus alone. 



2. Large Lymphocytes. These are of the same type as small 

 lymphocytes, but possessing more cytoplasm. The nucleus, while 

 round and taking a fairly deep rich violet stain, does not stain so deeply 

 as the nucleus of the small lymphocytes. The cytoplasm is a clear, 

 translucent, pure blue. It may contain pinkish granules known as azur 

 granules, but these are of rathei large size and do not mar the glass-like 

 appearance. They are from 9 to 15^ in diameter and are common in 

 children. In the acute lymphatic leukaemias they at times predominate. 



3. Large Mononuclears. -These are large round or oval cells with 

 a nucleus which has lost the richness of violet staining of the lymphocyte 

 nucleus. The nucleus is furthermore frequently irregular in outline 

 or may show the commencing indentation of the transitional nucleus. 



