426 The Philippine Journal of Science 1913 



3. Inoculation experiments {vaccination method) : 



a. One guinea pig was inoculated with the material from the left bubo, 



another one with material from the right bubo. They died of 

 plague on the third and fifth days, respectively. 



b. One guinea pig was inoculated with the material from the spleen. 



It died of plague on the third day. 



c. One guinea pig was inoculated with material from the nostrils ob- 



tained by swab. The animal survived, showing no indication of 

 plague. 



d. One guinea pig was inoculated with material from the rectum 



obtained by swab. It died of plague on the fifth day. 



Although plague infection among cats is apparently a rare 

 occurrence, the fact that cats may contract the disease in spite 

 of the high degree of resistance to plague infection has to be 

 considered from the hygienic standpoint. 



To appreciate the important role which cats may play in the 

 spreading of the disease one need only consider the close contact 

 of these animals with rats on one side and human beings on 

 the other. It is also a well-established fact that not only plague- 

 infected cats, but also those which have devoured plague-infected 

 material and remained apparently normal, may excrete plague 

 bacilli which have retained their full virulence. 



