LYMPHOCYTES. 157 



Without going into the various granule stainings so thoroughly 

 brought out by Ehrlich, we shall immediately take up the question of 

 a practical classification for use in making a differential count. As the 

 Romanowsky method of staining (Wright, Leishman or Giemsa) 

 gives us information not yielded by either haematoxylin and eosin or 

 the triacid, 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 

 leukocytes, it is convenient to divide such into basic ones, acid ones and 

 those which may be said to be on the border line betw r een these the 

 so-called neutrophilic affinities. 



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

 the granules of eosinophiles 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 polychroming). With the granules in the cyto- 

 plasm of the polymorphonuclears 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 

 preferring a simpler classification, it would seem proper to divide the 

 normal leukocytes into: 



1. Small lymphocytes. These are small round cells about the 

 size of a red corpuscle with a large centrally-placed, deeply violet stain- 

 ing nucleus and a narrow zone of cytoplasm. This cytoplasm may 

 not be more than a mere crescentic fringe. This is the type of lymph- 

 ocytes which makes up the greater proportion of the leukocytes in 

 chronic lymphatic leukaemia. At times these cells seem to be com- 

 posed 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 



