274 THE DIVISION OF LEUCOCYTES 



It was seen from the outset that it would be quite 

 impossible to count the number of granules contained 

 in lymphocytes, and the same could be said of those 

 of the common neutrophile leucocyte (fig. 76). But it 

 is possible to do so in the so-called eosinophile cells 

 (fig. 87). These cells have large granules, which stain 

 a deep scarlet with the polychrome dye, and therefore 

 these cells were chosen for this series of experiments, 

 especially as they are fairly common (2 to 4 per cent) . 



Three difficulties presented themselves in arranging 

 a technique for counting the number of eosinophile 

 granules : 



1. To the novice the basophile cell is sometimes 

 very difficult to distinguish by in-vitro staining from 

 the eosinophile cell, and mistakes seriously modify the 

 results. If specimens of each class of cell are seen 

 lying side by side (fig. 88) there is no difficulty in 

 distinguishing them, the eosinophile cell being much 

 the larger, although there is very little difference be- 

 tween the size of their granules. But in spite of the 

 fact that the cells rarely are thus found lying side by 

 side, with a little experience they can be readily dis- 

 tinguished; the granules of the basophile cell are more 

 discrete, and the lobes of its nucleus will practically 

 never stain by this in-vitro method. 



2. A living leucocyte is spherical in shape, and it 

 usually appears with its granules heaped one on top 

 of another, rendering it impossible to count them 

 accurately. 



3. If one attempts to count through the microscope 

 a group of granules not arranged in any definite order, 



