232 CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



2. In extensive skin diseases, especially pemphigus and 

 urticaria, there is often a great increase, but it occurs in so many 

 conditions that its diagnostic value is but slight (see p. 252). 



3. Diseases of the lungs.— In true asthma there is during the 

 paroxysms, and for a short time after them, a very decided 

 increase — to 10 per cent, or so. The cells in the sputum, too, 

 are practically all eosinophiles. This does not occur in the other 

 spasmodic diseases which so mimic true asthma, and is often of 

 critical importance in the diagnosis. Eosinophiles are never 

 found in the sputum in tuberculosis. 



4. Myelogenous leucocythcemia,. — Here there is an enormous abso- 

 lute increase in the total number of the eosinophiles, counting the 

 eosinophile myelocytes with them ; the percentage may not be 

 greater than in health. 



This is one of the most constant signs of the condition. 



A decrease of eosinophiles occurs in nearly all inflammatory 

 leucocytoses, especially in pneumonia, where a careful search over 

 many films may fail to reveal the presence of a single cell. Their 

 reappearance in any of these diseases is of distinctly good omen, 

 and one on which I place a good deal of reliance. It is not of 

 much value in pneumonia, as it does not occur till after the crisis, 

 but in chronic suppurative diseases, etc., a gradual increase in 

 the eosinophiles often heralds improvement. Neusser holds that 

 the same is true in tuberculosis also. 



Eosinophile Myelocytes. — The presence of these is practically 

 diagnostic of myelogenous leucocythaemia. 



Mast Cells. — These only occur in fractional percentages in any 

 disease, except myeloid leucocythaemia, where 5 or 10 per cent, is 

 common ; this is perhaps the most definite, constant, and readily 

 recognized sign of the disease. The large forms, with circular or 

 kidney-shaped nuclei, are practically only seen in this condition. 



Morphological Changes in the Red Corpuscles. 



Normal red corpuscles (Plate VIII., Fig. i) hardly need 

 description, and the practitioner can readily make himself 

 familiar with their appearance. They are strongly oxyphile, 

 staining pink with the eosin in Jenner's stain, and with acid 

 fuchsin in the triacid. It is especially important to become 

 familiar with their size, since modifications in this respect are 

 very important in the diagnosis of certain forms of anaemia. 



