62 IMMUNOLOGY 



According to Schilling the percentage of different kinds of white 

 cells in normal blood is : 



Basophiles 0.5 per cent 



Eosinophiles 2-4.0 per cent 



Myelocytes 0.0 per cent 



Juveniles (Metamyelocytes) 0.0 per cent 



Stabs .3-5.0 per cent 



Segmented 51-67.0 per cent 



Lymphocytes 21-35.0 per cent 



Mononuclears 4-8.0 per cent 



The myelocytes and metamyelocytes (juveniles) are bone mar- 

 row cells and give rise to the granulocytes of the peripheral circula- 

 tion. Gradwohl has described the myelocytes, juveniles and stabs 

 as follows: 



"Neutrophilic Myelocytes. — The cytoplasm of neutrophilic 

 myelocytes varies from very pale blue in the younger stages to 

 pink in the older forms. The nucleus varies in shape ; round, kid- 

 ney-shaped, or oval. It may or may not contain one or more 

 nucleoli, and is trabeculated. In leucemia the granules of the 

 myelocytes are very delicate and difficult to stain. They are pur- 

 ple and pinpoint in size. They are seen usually only here and 

 there; at times they may be entirely absent. In the blood stream 

 in severe infections, myelocytes usually have a pale blue cytoplasm 

 filled with coarse neutrophilic (purple) toxic granulation. The 

 myelocyte of leucemia has a fairly even periphery, while that of 

 infections is fragile, and consequently irregular. 



"Juvenile Neutrophiles. — Juvenile neutrophiles are found 

 normallj^ in the circulating blood in the percentage of to 1 per 

 100 leucocytes. They are slightly larger than the mature neutro- 

 philes. The cytoplasm varies from a bluish pink to a definite pink. 

 It is much wider than that of the myelocytes. The nucleus is 

 sausage-shaped to almost bean-shaped. It does not stain intensely, 

 and shows little or no chromatin structure, although it is definitely 

 divided into fields. It often contains one or more nucleoli, usually 

 situated in the end bulbs, which are definitely protruding struc- 

 tures. The granules are sometimes definite and sometimes very 

 fine. When they are coarse, thej^ are strikingly responsive to stain ; 

 when fine, they stain with difficulty. The same variations in .stain- 

 ing and structure- may be noted in leucemia and infections as is 

 seen in the mvelocA-tes. Thev are differentiated from 'stab' cells 



