128 PHALEN AND NICHOLS. 



be obtained. It will tlnis be seen that the great majority of the subjects 

 were adult males, and thus the results obtained from the examinations 

 are not entirely representative of the entire population. 



So far as sex is concerned, the error thus introduced is probably of 

 little moment, as the occupations and habits, and therefore the op- 

 portunities for infection are much the same for the women of the Phil- 

 ippines, especially for the classes here considered, as for the men. Of 

 the number examined by us 93 were women, of whom 3 were infected, 

 indicating a percentage of infection among females of about the same as 

 for the entire number of examinations. Of 35 subjects afflicted with 

 elephantoid disease observed in the Provinces of Albay and Sorsogon, 

 14 were women. 



With regard to age also the subjects were not entirely representative 

 of the whole population. A very large majority of the persons examined 

 were between 20 and 30 years. The filarial infection, once introduced, 

 persists indefinitely, probably aided by frequent auto-inoculation in the 

 presence of suitable mosquitoes. It is therefore reasonable to suppose 

 that the number of such infections would be in nearly direct ratio to 

 the age. In the subjects affected with elephantiasis, before mentioned, 

 the average age at the incidence of the disease was about 35 years. 

 Allowing then for a smaller number of infections in the young and a 

 larger number in those of middle age and in older individuals, our 

 subjects should represent a fair average of the general population. 



The subjects examined are representative of the mass of the Filipino 

 people, although the highest class is not represented and the lowest 

 laboring class by but a very small number. Besides the Filipinos, several 

 hundred Moros were included in the examinations and a few Chinese and 

 Japanese residents. 



The examinations have been made either by the writers or by medical 

 ofiicers of the Army at the several stations occupied by native troops, 

 known as Philippine Scouts. Including American negro soldiers, a 

 total of 6,804 cases have been examined for filaria; 3,447 by the 

 Tropical Board, and 3,357 by medical officers as shown in the accompany- 

 ing table (Table II). The findings given in each case have been 

 confirmed by us. 



III. METHODS. 



The chief surgeon of the division issued a circular requesting either 

 that an examination be made of the men of each command by the local 

 medical officer or that suitable specimens be taken and forwarded to the 

 Army Tropical Board for examination. The circular of instruction re- 

 quested the examination of fresh specimens of blood taken after 9 o'clock 



