82 APPLIED PHYSIOLOGY 



no doubt these morphological differences must mean 

 corresponding differences in function. As regards the 

 mutual relations of the different varieties of white cell, 

 investigators are at present divided into two camps. On 

 the one hand are those who assert that they are all 

 derived from a single type of cell, and that the non- 

 granular can develop into the granular forms; on the 

 other hand are those who maintain that, as regards the 

 non-granular and the granular cells, at all events, no 

 relationship exists, and that the one never changes into 

 the other. Into the merits of the controversy one cannot 

 enter here, but it is possible that, as in so many cases, 

 truth lies in a compromise between the two views, and 

 that whilst, if one goes far enough back, the two sets of 

 cells will be found to have a common origin, yet once 

 they have attained their distinctive features, and are 

 free in the blood-stream, no further transition occurs. 



The varieties of white cell in normal blood may be 

 grouped as follows : 



1. Non-granular : 



(a) Lymphocytes (large and small), 23 per cent. 



(b) Large mononuclears, 2 per cent. 



2. Granular : 



(a) Polymorphonuclear, with abundant neutrophil 



granulations, 70 per cent. 



(b) Transitionals, with very few neutrophil granu- 



lations, 1 per cent. 



(c) Eosinophils, 3 per cent. 



(d) Basophils, 0*5 per cent. 



The morphological details exhibited by these different 



