VIII, B, 2 Heiser: Plague in Manila during 1912 115 



people who work along the water front or with persons who had 

 recently been in a plague-infected country, it seems reasonable 

 to infer that the disease was not introduced by human beings. 

 On account of the facts that no infection has as yet been found 

 among the rats of the water front, and especially since the 

 wharves have remained free from rats and are practically rat 

 proof, it does not seem probable that infected rats could have 

 come from a ship by means of gangways, cargo chutes, or lines 

 of a vessel. This is rendered still more unlikely because vessels 

 from plague-infected ports are fumigated with sulphur at least 

 twice annually. Rice vessels and other ships that are especially 

 liable to have rats on board are fumigated upon every trip. 

 After the detection of human cases, in April, on arriving vessels, 

 all ships coming from Hongkong and Amoy were fumigated on 

 every trip. All dead rats found aboard ships were sent to the 

 laboratory, but all proved negative for plague. From the fore- 

 going it is evident that, reasoning by exclusion, infected rats 

 were probably introduced in cargo. This seems very probable, 

 in view of the enormous quantities of food supplies and other 

 cargo which come almost daily from plague-infected centers in 

 China and Japan. For instance, there are literally thousands 

 of baskets of eggs, garlic, onions, and similar foodstuffs among 

 which rats could easily take refuge, that come from places like 

 Canton or Amoy, within the period of five days. It is well 

 known that plague has existed in Canton almost continuously dur- 

 ing the past ten years, and it is not improbable that plague might 

 have been introduced in this way. There are also large quan- 

 tities of cargo arriving from Japan, especially glass and china- 

 ware, and other things which are packed in hay and straw, and 

 which afford favorite harboring places for rats. 



The disease might have been introduced through the means 

 of infected bedbugs. In a case of human plague which was taken 

 from 508 Calle Magdalena, bedbugs were caught from the 

 petate (straw mat) upon which the man died, and smears made 

 from the intestinal contents showed plague-like bacilli ; the patho- 

 logical findings, however, were not confirmatory. It is not 

 impossible that bedbugs may have been concerned in the intro- 

 duction of the disease. On account of the fact, however, that 

 all second- and third-class passengers' clothing and effects are 

 steamed at Mariveles, it does not seem likely that bedbugs could 

 have been introduced with them. 



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