TWELFTH ANNUAL REPORT 49 



reference to malaria. The part taken by the Bureau of Science 

 in this investigation includes: 



1. A topographical survey with maps of the region. 



2. An entomological survey, with especial reference to the habits and 



breeding places of flies and mosquitoes capable of transmitting malaria. 



3. The collection and microscopic examination of blood smears for malarial 



parasites from 1,098 persons. 



4. The examination of a limited number of stool specimens to determine 



the intestinal parasite irrJ:>- 



5. A study of the comparative value of the "spleen index" and of rnicros- 



copic examination of the blood in the diagnosis of malaria. 



The results of the investigation of this commission, which will 

 supply an important contribution to the epidemiology of malaria 

 and to the prophylaxis of the disease as it exists in the Philippine 

 Islands, will appear in an early number of Section B of The 

 Philippine Journal of Science. 



Surra. — An investigation of the therapeutic action of certain 

 drugs and chemicals upon surra has been undertaken, but is at 

 present suspended awaiting the arrival of chemicals from abroad. 



Helmintholoyy. — The essential facts of the life history of the 

 worm {(Esophagostomum apiostomum) of the nodular intestinal 

 disease, which is a frequent parasite of apes and occasion- 

 ally of man, have been worked out, and experiments are in 

 progress to determine the methods of infection with this parasite. 

 It is probable that the larva is capable of penetrating the skin 

 of man as is the case of the larva of the hookworm. 



The domesticated pig as a "carii^er" of infections. — It is al- 

 ready known that the pig is a source of infection to man in the 

 case of the pork tapeworm {Tseyiia solium) and the muscle 

 worm (Trichinella spiralis), but no definite knowledge is had 

 of the role it plays in the spread of other diseases and parasites. 

 The fact that domesticated pigs commonly live near or under 

 the houses of Filipinos and the part the pig plays as a scavenger 

 in the Philippine Islands have led us to investigate the pos- 

 sibility of these animals becoming infected with, and acting as 

 "carriers" of, intestinal diseases and parasites communicable to 

 man. The present investigation included a determination of 

 the intestinal parasites occurring naturally in the pig, and ex- 

 periments with bacillary dysentery, cholera, entamcebic dysen- 

 tery, and balantidiasis, and with the hookworm and other 

 intestinal worms. The results of these experiments have led 

 to the conclusions that the domesticated pig cannot be infected 

 with, and consequently plays no role in the dissemination of, 

 cholera, bacillary dysentery, entamcebic dysentery, or hookworm 



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