CAUSE OF THE REAPPEARANCE OF CHOLERA. 93 



a mile or more apart, and the most careful investigation fails to reveal 

 any connection whatsoever between the infections. After this beginning 

 the disease seems to increase in virulence and gradually commences to 

 attack persons who are better nourished and fed, until finally more 

 resistant persons like Europeans, the better class of Filipinos, and 

 Americans become victims. 



It has been most difficult to explain the presence of cholera in Bilibid 

 Prison each time that it makes its reappearance in the city of Manila. 

 In this institution sterilized water is supposed to be invariably furnished 

 and only cooked foods are served and every reasonable precaution is 

 taken. The outbreaks in this institution have heretofore never beep 

 satisfactorily traced or accounted for. 



The practical observation made several years ago that an outbreak of 

 cholera is never severe in a community which was afflicted within two 

 years has been of great assistance in combating this disease. Another 

 noteworthy fact is that a much larger percentage of cases occurs among 

 the Japanese than among any other nationality, and this is particularly 

 true of the Japanese fishermen who leave the shore every evening at sun- 

 down and spend the night upon the bay in fishing; returning again 

 about daylight. These men are usually attacked during the latter portion 

 of the night. 



The appearance of the disease in the provinces which are accessible 

 from Manila by land apparently is never preceded by the suspicious 

 deaths which have been observed in this city, and so far there has been 

 very little difficulty in tracing such outbreaks to a previous case. On the 

 other hand, those which have occurred in the Provinces of Iloilo, Samar, 

 and Leyte (see Map No. 2), which are separated from Manila by the open 

 sea, have invariably begun among the poorest members of the community 

 and the first cases could not be traced to a previously infected person. 



FACTORS SUGGESTING HYPOTHESIS. 



During the past five years in order that improved methods for stamp- 

 ing out cholera might be devised, every endeavor has been made to for- 

 mulate a hypothesis which would explain the appearance of this disease 

 under such unusual circumstances, but up to within a few weeks ago this 

 has been impossible. In consequence, it has not been practicable com- 

 pletely to eradicate the cholera from the Islands by employing the usual 

 sanitary measures. Of course, it is well known that if all the residents 

 of a community could be induced to drink sterile water and eat cooked 

 foods the disappearance of cholera invariably wuld take place, but with a 

 population like that of the Philippine Islands, it will be obvious to those 

 who have had experience with local conditions that many years of 

 education would be required before a result of this kind could be hoped 

 for; so that if greater success is to be expected, a more direct method of 



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