ARNETH'S NUCLEAR CLASSIFICATION. 413 



much evidence as to the number of white cells per cubic millimeter in the 

 blood of healthy natives. Our own work on 29 adult male Filipinos gave 

 an average count of 9,248. This may seem a trifle high, but it is at least 

 well within the normal upper limit of 10,000 given by Simon, Buchanan 

 and Cabot. 



It may be mentioned that our average of 9,248 agrees closely with the 

 average of 9,000 given by Castellani and Chalmers for adult male Ben- 

 galese in India. 



Summary. — After a consideration of the above four sections it will 

 be evident that in our series of Filipino bloods there is : First, an absolute 

 number of white cells within normal limits ; second, a markedly low rela- 

 tive proportion of polymorphonuclear neutrophiles ; and third, an abnor- 

 mally high percentage of the neutrophilic elements which fall in classes 

 I and II of Ameth and which are supposed to be deficient in phagocjrtic 

 power. Therefore, in the Filipino blood there is both a relative and 

 an absolute reduction in the phagocytes, the cells which, with the aid of 

 opsonins, are concerned in destroying bacterial invaders. 



If this state of things is general in tropical races, it may be a visible 

 indication of the lowered resistance of such peoples to certain newly 

 introduced maladies and to some epidemic tropical diseases which gen- 

 erally cause a higher mortality among natives than is experienced among 

 Caucasians. In the first class of diseases may be mentioned measles, 

 leprosy, syphilis, and tuberculosis, and in the second class plague and 

 cholera. Apparently the natives of the Philippines have a good resistance 

 to infections with staphylococci and streptococci, and this clinical fact 

 may be related to the observations of Buchanan who could find no rela- 

 tionship between the degree of nuclear subdivision and the number of 

 cocci engulfed by the neutrophilic cells. 



POSSIBLE INFLUENCE OF TROPICAL CLIMATE. 



Whether the reduction we have found in the phagocytic elements of 

 the blood may be the result of a tropical climate per se is an interesting 

 subject for speculation and for future study. About a year ago we 

 suggested (9) that the low polymorphonuclear count in natives and white 

 men in the Philippines might indicate lowered resistance and be due to 

 tropical conditions. The work of Wickline showiiag that the decrease 

 of polymorphonuclear elements becomes progressively more marked as 

 the length of residence in the Philippines increases, is suggestive that 

 the change is due to the climate. Our recent work with the Arneth 

 classification points in the same direction, since the index for white 

 men who had lived over a year in the Islands is a little higher than 

 has been found normal in temperate climates by most observers. On 

 account of the many complicating factors, three of which are mentioned 

 below, it will be extremely difficult to establish a direct relationship 

 between climate and diminished phagocytic power. 



