•;: -, 



"* -'v 



■ 



, Photograph from Zuschlag 



RATS BEING OFFICIALLY COLLECTED IN COPENHAGEN DURING 

 THE ZUSCHLAG CAMPAIGN 



The chronicles of the sea, before the 

 development of steam power, contain 

 many grisly tales of plague ships drift- 

 ing helplessly on the ocean, their crews 

 stricken with the mortal disease which 

 we now know must have been carried on 

 board by rats. The serious menace from 

 this source still exists in the face of all 

 our modern knowledge. 



In the fifteen years following the out- 

 break of plague in Canton, China, in 

 1894, this disease was discovered on 156 

 ships, and 51 countries are known to have 

 been infected through its distribution by 

 commerce. 



The disease was introduced into the 

 United States at San Francisco, where, 

 in order to control it, the United States 

 Public Health Service made a successful 



campaign against rats, 

 which resulted in rat- 

 proofing much of the 

 city, and thus mate- 

 rially bettering condi- 

 tions. 



Meanwhile, unfor- 

 tunately, the plague- 

 bearing rats had 

 passed the disease on 

 to ground squirrels 

 living abundantly in 

 the hills surrounding 

 San Francisco. Ow- 

 ing to the wide-spread 

 distribution of ground 

 squirrels in the United 

 States, their proved 

 susceptibility to this 

 disease greatly in- 

 creases the danger of 

 future outbreaks of 

 the plague in this 

 country. 



When it was learned 

 that the bubonic 

 plague is a rat disease 

 which is transmitted 

 to human beings by 

 fleas, it became possi- 

 ble to fight it with in- 

 telligence. Owing to 

 the universal distribu- 

 tion of rats and the 

 increase of commerce 

 between communities, 

 the need of incessant 

 vigilance to guard 

 against sudden outbreaks of the plague 

 is evident. 



Only through the elimination of these 

 rodents, or a very great reduction of 

 their numbers and their control, can the 

 world feel secure from this dread dis- 

 ease. Although the upkeep of quaran- 

 tine precautions and other defensive 

 measures against rats in the ports of the 

 world, as well as in interior cities, 

 amounts yearly to a great sum, it is 

 worth all it costs. 



In addition to transmitting the bubonic 

 plague, the house rat is known to convey 

 infection of trichinosis, septic pneumo- 

 nia, epidemic jaundice, and rat-bite fever. 

 It is also afflicted with rat-leprosy, a dis- 

 ease so like human leprosy that they are 

 scarcely distinguishable, and the relation- 



14 



