DIFFERENTIAL LEUCOCYTE COUNT 263 



B. CELLS CONTAINING TRUE GRANULES IN THEIR PROTOPLASM. 



i. Polynuclear Leucocytes (Plate VII., Fig. 7). These are 

 rather larger than a red corpuscle, and have a nucleus which 

 is twisted into various irregular shapes; it is often deeply 

 lobed, so that it appears to be multiple, but is always really 

 single except in degenerated forms. 



It contains in its protoplasm numerous very fine granules 

 of a substance which stains pink with the eosin in Jenner's 

 stain, and which are therefore considered by many English 

 pathologists to be fine eosinophile granules. With triacid 

 stain they are a sort of copper colour, quite unlike the large 

 eosinophile granules, and are frequently spoken of as neutro- 

 phile. The term is a convenient one, whatever the scientific 

 justification for it. 



They vary in numbers between rather wide limits. In the 

 adult 70 per cent, is a fair average, but they may be much 

 higher, and approach 80 per cent. In childhood they are 

 much less numerous (30 to 40 per cent.). 



i a. Myelocytes or Neutrophile Myelocytes. These are the 

 mother-cells of the above, and do not occur in the blood in 

 health, but may be found in the bone-marrow. There are 

 two varieties. 



Cornil's myelocyte is usually a very large cell with a large, 

 faint-staining round or kidney-shaped nucleus, often placed 

 decidedly to one side of the cell or even touching the peri- 

 phery. The protoplasm is relatively scanty and contains 

 neutrophile granules, often in very small numbers and of 

 feeble staining power. It is often necessary to use triacid 

 stain to demonstrate them; neglect to do this may lead to 

 their being confounded with large lymphocytes or hyaline 

 cells (Plate VII., Fig. 11). 



Ehrlich's myelocyte is similar to the above, but smaller; it 

 is usually rather larger than a polynuclear. It has a round 

 or oval nucleus, which is often central or but slightly excen- 

 tric, and which stains deeper than that of Cornil's myelocyte, 

 but not so deeply as that of a polynuclear. Its neutrophile 

 granules are usually distinct (Plate VII., Fig. 10). 



Cornil's myelocyte is probably derived from Ehrlich's by 

 a process of degeneration, especially dropsy of the nucleus. 



