114 The Philippine Journal of Science 1920 
the failure to report cases early, were the factors that, more 
than any others, operated to make cholera suppression difficult. 
McLaughlin concluded from his experience in these outbreaks 
that the most important réle in the transmission was played by 
the carriers. As a result of this important discovery, it has 
been suspected that possibly some carriers were introduced from 
near-by foreign countries, and since then the routine practice 
of examining the stools of all steerage passengers from cholera- 
infected districts was followed; at the same time the examination 
of the feeces of all suspects, and of all persons engaged in hand- 
ling food for public consumption, became also a routine practice. 
All carriers were sent to San Lazaro Hospital, and there de- 
tained until the vibrios disappeared from their stools. 
In July, 1911, seven contacts of a positive case proved to be 
carriers, but none of them developed cholera. All of these were 
retained till the vibrios disappeared, and no more cases developed. 
One carrier was discovered in a Chinese immigrant from Canton. 
Hence the possibility that some outbreaks were caused by car- 
riers from abroad was considered. 
In August, 1913, there was another outbreak of cholera, the 
first cases occurring in widely separated places with apparently 
no connection between them. All carriers found were isolated 
in cholera hospitals or other quarters, and the outbreak was 
suppressed. 
In the same way the 1914 outbreak was suppressed by the 
isolation of cases and carriers. The disease seemed not to have 
been introduced from foreign countries, since no carriers were 
detected during the quarantine period. That year the cholera- 
carrier survey was more extensive, including the personnel of 
all establishments selling food, and remote contacts, such as 
persons living in the same block where a suspected case or a 
positive carrier was found. As a result it was found that out 
of 37,160 specimens, 530, or 1.42 per cent, were carriers. One 
important discovery took place in Bilibid Prison where out of 
179 carriers, 5 developed the symptoms of cholera from four to 
eighteen days after having been found positive for the vibrios. 
In 1914 carriers were also detected in the bodies of those dead 
of other diseases, such as enteritis, diarrhoea, dysentery, in- 
_ fantile beriberi, pulmonary tuberculosis, and intestinal tuber- 
culosis. These findings led Munson to the belief that possibly 
any intestinal disorder materially predisposes to the develop- 
ment of cholera infection if the latter gains access to the alimen- 
tary tract. 
