162 NORMAL AND PATHOLOGICAL BLOOD 



a reduction in the number of the white cells. Pernicious anaemia 

 shows a marked leukopenia, as is also the case with Banti's disease. 

 Two tropical diseases, Kala-azar and dengue, show a marked leuko- 

 penia, the counts often being below 2500. During the apyrexial 

 period of malaria we may have a white count of 5000. 



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 of trichinosis is best known, and a combination of 

 this blood finding with fever and marked pains of muscles, would 

 justify the excision of a piece of muscle for examination for encysted 

 embryos. In true asthma eosinophilia is marked, and its absence is of 

 value in indicating other causes for the condition. Certain skin 

 diseases, especially pemphigus, also show eosinophilia. 



LEUKOCYTOSIS. 



It is to an increase in the polymorphonuclears that this term is 

 usually applied, the term lymphocytosis or eosinophilia being em- 

 ployed where white cells of eosinophile or lymphocyte nature are 

 increased. We have physiological leukocytosis in the latter weeks of 

 pregnancy, also in the new-born, and in connection with digestion. 



Pathological Leukocytosis. Pneumonia. In this disease we 

 have a leukocytosis of 20,000 to 30,000 or higher. The eosinophiles 

 are almost absent. A normal leukocyte count in pneumonia makes a 

 prognosis unfavorable. 



Septic processes. The leukocyte count is of great value, especially 

 when we obtain a leukocytosis with 80 to 90% of polymorphonuclears, 

 as in appendicitis, cholecystitis or other suppurative conditions. 



According to Cabot, leukocytosis varies in infections as follows: 



i. Severe infection good resistance; early marked and 

 persistent leukocytosis. 



