10 Harry C. Schmeisser. 



the extreme limits are between 20,000 and 80,000 per c. mm. Propor- 

 tion of whites to reds, lowest limit, 1/40; average, 1/50-1/150. 



Haemoglobin (Sahli). This shows considerable variation, lowest 

 limit, 45 per cent ; highest, 75 per cent; average, 60-70 per cent. 



Blood Smears. Wilson's stain was found to give the best results, 

 especially when applied immediately after the smears were made. 



Classification of blood cells (Fig. 1). 



Erythrocyte. 



1. Normocyte (a) : Elliptical disk. Nucleus, same shape as cell, 

 deep blue, slightly picnotic. Cytoplasm yellow and glassy. (Both cell 

 and nucleus uniform in size, shape and staining). 



Blood Platelet (6). 



Length of normocyte, width less than that of normocyte. Nucleus 

 round, purple, chromatin diffuse, diameter equal to width of its 

 cell. Cytoplasm pale gray with vacuoles about nucleus, frequently con- 

 taining small circumscribed red structures. May vary in size and 

 shape. 



Leucocytes. 



1. Polymorphonuclear leucocyte with eosinophilic rods (c) : Bound, 

 diameter about length of normocyte. Nucleus has two or more lobes, 

 pale blue, chromatin diffuse. Cytoplasm colorless with bright red, 

 spindle-shaped rods. 



2. Polymorphonuclear leucocyte with eosinophilic granules (d) : 

 About the same in shape and size. Nucleus has two or more lobes, 

 purple, slightly picnotic. Cytoplasm faintly blue with dull red 

 granules. 



3. Lymphocyte (e, e') : Round, diameter about width of normocyte. 

 Nucleus round, purple, chromatin diffuse. Cytoplasm small in amount, 

 to one side of nucleus, pale blue. Same cell may be slightly larger. 

 Thus a division into the small (e) and large (e') lymphocyte may be 

 made. 



4. Large mononuclear cell (/) : Round or oval, diameter about 

 length of normocyte (at times, more or less). Nucleus round, oval or 

 slightly irregular, and larger, otherwise similar to nucleus of 

 lymphocyte. Cytoplasm abundant, completely surrounds nucleus, pale 

 blue. (A suggestion of fine granules.) 



