UNITED STATES DEPARTMENT OF AGRICULTURE 
BUREAU or BIOLOGICAL SURVEY 
WASHINGTON, D. C. 
June 27,1912 
I'ln. Alex V/etrnore 
San Juan, Porto Rico 
Dear Mr. V/etaore: 
t 
You have no doubt heard ere this that the bubonic plague has 
made its appearance in Porto Rico. So far as I can learn from the 
papers, the disease is confined to the Island of San Juan, as you 
will notice from the clipping enclosed. Modern methods in relation 
to plague are such that there is very little difficulty as a rule 
in confining the infection to the very limited area in which it 
appears. As perhaps you know, it is transmitted from rat to rat 
and from rat to other small mammals like ground squirrels and to 
human beings solely(so far as at present known) by fleas. It is 
well, therefore, to avoid entering a territory knovm to be infected 
with plague, especially along the harbor front of ajtort, as here, 
infected rats are numerous. 
I was in the Hawaiian Islands during the existence of plague 
(in 1889) and personally have no fear of the disease, if the sim- 
plest precautions are taken. Stevedores and others working about 
» 
wharves and natives going barefoot in the infected territory, so 
that the Ileas have easy access to the na.ked skin, are the ones 
that are usually bitten by fleas; others are practically iraniune. 
Very truly yours, 
Chi eT , Bi olbgi cal Survey, 
