﻿IX, B, 2 Sanitary Survey in Mindoro 181 



their families ; and, secondly, the inability properly to assimilate 

 satisfactory food products, provided these are obtainable. 



The general question of clinical inefficiency is largely an eco- 

 nomic one, but nevertheless it is one of the most important 

 phases of the complex problem of health and sanitation in Min- 

 doro, as well as in other parts of the Philippine Islands. 



7. A COMPARISON OF THE SPLEEN INDEX WITH THE MICRO- 

 SCOPIC EXAMINATION OF THE BLOOD FOR MALARIAL PARASITES 

 IN 1,003 PERSONS 



By Ernest Linwood Walker and Seth L. Cox 



There are two methods in general use for obtaining the index 

 of malarial infection in any region. One of these is by micro- 

 scopic examination of the blood of a certain portion of the 

 inhabitants for malarial parasites; the other is by the determi- 

 nation by palpation of the number of the individuals having 

 enlarged spleens. Both methods have their application and their 

 limitations. The microscopic examination of the blood is espe- 

 cially applicable for determining the incidence among nonim- 

 mune persons. The advantages of this method are that it is 

 more apt to discover recent infections and that its results are 

 direct and unequivocal; its disadvantages and limitations are, 

 first, the time required to make an adequate research of the blood 

 of a sufficient number of individuals; and, secondly, the fact 

 that the parasites cannot always be found in the peripheral 

 blood, especially in chronic cases. The spleen index is especially 

 applicable to the determination of the endemicity in a malarial 

 region. It is a convenient and quick method; but it is subject 

 to the errors that enlargement of the spleen in the tropics may 

 be due to causes other than malaria, that it is considered reliable 

 only when applied to children between the ages of from 1 to 

 10 years, and that it may not indicate recent infections in which 

 the spleen had not yet become enlarged. 



In the laboratory examinations of about one-third of the 

 population of San Jose, a relatively large proportion of indi- 

 viduals was found to harbor malarial parasites in the blood, and 

 in the physical examinations of these same persons a nearly 

 equal proportion was found to have enlarged spleens. There- 

 fore, it has seemed worth while to compare the two series 

 in order to determine how far they coincided. This could 

 readily be done, as the two series of examinations were made 

 on the same persons and the individuals of each series could be 

 identified by their company number. 



