PLAGUE AND BACILLUS PESTTS 823 



An excellent example of the circumscription of a plague focus 

 at its first discovery is one which we take from a note by Rucker 

 in the United States Public Health Service Report, No. 28, 1915, 

 based largely on the work of Passed Assist. Surg. R. A. Kearny. 



In September, 1914, a dead Mus norvegicus was found on a street corner 

 in New Orleans. Laboratory examination proved this plague infected. The 

 district was searched for other rats and on the 16th of September a similar 

 plague rat was found in the neighborhood in a Chinese restaurant located 

 in a ramshackle frame building, situated between a rat-proof brick building 

 and an open lot. Behind the restaurant was a frame shed which was not 

 rat proof. A survey of the district followed, in which thirty-eight infected 

 rats were discovered, all of them of the same species as the preceding. One 

 hundred and thirteen dead rats were found, and two infected rats were found 

 on a neighboring street corner. Twenty-one were found in the Chinese 

 restaurant, and one in the open lot and the other in the neighborhood. Rucker 

 believes that the focus was eliminated largely because there was plenty of food 

 in this particular neighborhood, and rats could not easily leave there without 

 entering the street, a thing which they would have done only under the 

 pressure of shortage of food supply. He calls attention to the fact that 

 if this had been a focus of Mus ratus or Mus alexandrinus which are climbing 

 rats, the original focus would rapidly have been spread. But since the 

 Mus norvegicus is a ground rat, it was closed in by the neighboring brick 

 walls. In the operations following these discoveries, the building chiefly 

 infested was torn down and the frame sheds behind it were rendered not 

 inhabitable for rats. Many rats were found dead and a considerable number 

 were killed. Fumigation was carried out on the premises, and these and 

 other premises washed down with tank oil for the purpose of killing fleas. 

 Very few rats escaped. An interesting control was carried out which has 

 been introduced into plague campaigns, namely, that guinea-pigs were placed 

 into the fumigated premises after fumigation. One of these contracted plague 

 and died, and the place was, therefore, refumigated. Guinea-pigs which 

 had been used as controls in other places remained alive. Only one human 

 case was attributable to this focus. 



A Bulletin published by the United States Public Health Service 

 in November, 1920, (35, No. 45) has laid down ordinances for rat- 

 proofing. These we quote in toto directly from this Bulletin. 



"The rat-proofing of buildings is generally secured either by elevation 

 of the structure, with the underpinning open and free, or by marginal 

 rat-proof walls of concrete or of stone or brick laid in cement mortar, 

 sunk two feet into the ground, and fitting flush to the floor above. The 

 wall must fit tightly to the flooring and not merely extend to the joists or 



