173 



The evacuation or burning of buildings can hardly be called a suc- 

 cessful measure any more than a retreat can be styled a victory; 

 moreover, there can be no question from an economic standpoint 

 as to the value of rat proofing over abandonment except in a few 

 isolated cases of dilapidated insanitary property. 



Schemes and plans for demurization, total or partial, have been 

 as numerous and varied as they have been unsuccessful. Traps and 

 poisons have been the agencies of destruction, but until some highly 

 communicable epizootic peculiar to rodents shall have been dis- 

 covered, absolute eradication of the rat can be considered as nothing 

 less than impossible. 



A recognized authority on plague, Major Morehead, of the Indian 

 Medical Service, states that "rat destruction is of doubtful value," 

 referring, of course, to trapping and poisoning when those measures 

 are used solely without auxiliary measures. He agrees with Japa- 

 nese authorities in their arguments that as rat populations decrease, 

 the breeding rate among survivors increases, due, obviously, in part 

 at least, to increased food supply and harboring facilities. Such a 

 result is assured where rat proofing is not accomplished at the same 

 time. This latter procedure, by destroying rat harborages and cut- 

 ting off food supplies bring about conditions unfavorable to breeding. 



The total eradication of rats in a locality is not absolutely neces- 

 sary, however, to the eradication of plague. If the. rat population 

 is kept within fairly low limits, rat centers destroyed, and such rat 

 population as does exist well scattered and not congested, it is ven- 

 tured that rat plague will disappear from a locality. Plague among 

 rats in San Francisco ceased to appear when the number of rodents 

 was reduced some 50 per cent, but such reduction was accomplished 

 only after six months of ceaseless endeavor, which included also the 

 rat proofing of the bakeries, stables, and markets in the city. 



It is a logical supposition that close contact is just as essential 

 for the propagation of plague among rats as it is for the spread of 

 certain communicable diseases among human beings, the increase 

 of cases being in direct proportion to the density of population and 

 closeness of contact. 



RAT PROOFING OF PRIMARY IMPORTANCE. 



Without the general enforcement of rat proofing antiplague meas- 

 ures are bound to be more or less temporary and decidedly unsatis- 

 factory. This subject is of immense importance to the public, both 

 from a sanitary and a commercial standpoint, but the latter aspect 

 of the question is more apt to prove of interest to most communities. 



The measures necessary to render buildings rat proof are the 

 same, however, whether they be instituted for sanitary or for com- 

 mercial reasons. Rat proofing will, therefore, be considered entirely 



