212 CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



be very great, as in trichinosis, where the eosinophiles. usually 

 form 40 to 80 per cent, of all leucocytes, a fact of great import- 

 ance, and absolutely distinguishing the disease from typhoid 

 fever, rheumatism, and other diseases which may be confounded 

 with it ; rarely, however, there may be no eosinophilia, so that 

 its absence does not definitely exclude the disease. In bilharzia 

 disease there is often, though not always, a mild eosinophilia. 

 There is practically always an increase in ankylostomiasis. It 

 may be moderate, or may reach 70 per cent. This fact enables 

 infected individuals to be picked out of a gang of workmen with 

 much less trouble than by an examination of the faeces. In 

 diseases due to other intestinal worms (ascarides, oxyuris, taeniae), 

 there may or may not be eosinophilia. 



In hydatid disease there is frequently a moderate eosinophilia, 

 and sometimes a great one. This is important in the diagnosis 

 between hydatid and abscess of the liver, since in the latter 

 condition the eosinophiles are usually scanty. In such a case 

 the higher the count is above 4 per cent., the more likely is the 

 disease to be hydatid, and vice versa. 



In the only case of cysticercus I have seen the eosinophiles 

 ranged between 5 and 7 per cent. 



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. 232). 



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 leucocythamia.- — Here there is an enormous abso- 

 lute increase in the total numbers 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 



