196 NORMAL AND PATHOLOGICAL BLOOD 



LEUKOPENIA. 



This is a term used to designate a reduction in the normal number 

 of leukocytes. A leukocyte count of 5000 would represent a slight 

 leukopenia; one of 2000, a marked leukopenia. In the later stages 

 of typhoid, and in acute miliary tuberculosis, we expect a moderate 

 leukopenia. 



The leukopenia of typhoid is moderate and is often preceded in the first few 

 days by a moderate neutrophile leukocytosis. Later on we have a decided increase 

 in the lymphocytes. A marked diminution or absence of eosinophiles is so character- 

 istic that any increase in eosinophilic percentage negatives a diagnosis of typhoid. 



Paratyphoid gives a similar blood picture. 



Chronic alcoholism and chronic arsenic poisoning cause a reduction 

 in the number of the white cells. Pernicious anaemia shows a marked 

 leukopenia, as is also the case with Band's disease. Two tropical dis- 

 eases, kala-azar and dengue, show a marked leukopenia, the counts 

 often being below 2500. During the apyrexial period of malaria we 

 may have a white count of 5000, ^ 



It has recently been claimed that a leukopenia with a. coincident 

 marked reduction in the lymphocytes is characteristic of ifceasles and 

 that this occurs several days before the Koplik spots appear?*v 



Kocher notes that in exophthalmic goiter the leukocyte count is considerably 

 diminished and that the polymorphonuclears are not much more than one-half the 

 usual percentage while the percentage of the lymphocytes is almost double the 

 normal. 



X-ray treatment tends to destroy leukocytes in the exposed region, especially 

 polymorphonuclears. The small lymphocytes are least affected. 



EOSINOPHILIA. 



Where the eosinophiles are increased to 5%, we have a moderate 

 eosinophilia. In some cases of infection with intestinal parasites, 

 especially hook-worms, but also from other parasites, as round and 

 whip-worms, we may have an eosinophilia of 30 to 50%. In Guam, 

 among the natives, it is difficult to find an eosinophile count under 15%. 

 The eosinophilia tends to disappear when the anaemia becomes very 

 severe. 



The eosinophilia of trichinosis is best known, and a combination of 

 this blood finding with fever and marked pains of mucles, would justify 

 the excision of a piece of muscle for examination for encysted embryos. 



