PROPHYLAXIS OF MALARIA. 
13 
reached the very small noneffective rate of 0.18 and the admission 
rate of 8.79. In the Philippines on the other hand (Chart No. V) 
the decrease has not been as steady, and in 1912 and 1913 the ad¬ 
mission rates are higher than in 1910 or 1911. The exact reason for 
this increase during the years mentioned is not known but it was 
probably due to more exposure in the field because of local maneuvers 
or expeditions. 
The decrease of malaria in the Army has been brought about 
largely by measures directed against the mosquitoes transmitting 
the disease, and the protection of man from the bites of these insects. 
Quinine prophylaxis has probably had but little to do with this re¬ 
duction, as the use of this method has been very limited. Neither 
has the control of treatment by microscopic examinations of the 
blood and the treatment of “ carriers " and latent infections operated 
to any extent in reducing the disease in the Army, as these methods 
have been very little used, and it is believed that had these methods 
been widely employed the reduction of malaria would have been 
much more marked and much more rapid than it has been. 
The methods of prophylaxis adopted in different localities must 
vary with the peculiar conditions present in each region, and com¬ 
mon sense must be used here as in every other procedure for the 
prevention of disease. High-flown theories must give place to a 
calm study of the situation and the means most applicable and best 
adapted to fighting the infection. Under some conditions we may 
be able to practically eradicate mosquitoes, while under others this 
measure may be impossible, and quinine prophylaxis will have to be 
substituted, together with measures for the protection of man from 
the bites of mosquitoes. In many, if not most, localities the best 
results will be secured by the combination of several prophylactic 
measures, and I am not at all in sympathy with those who insist that 
•either upon the destruction of mosquitoes or the prophylactic use of 
quinine alone we must depend for success in the prevention of the 
malarial fevers. 
The prophylaxis of malaria, to be successful, must rest upon a 
thorough knowledge of the etiolog}^ of these infections. In the past 
much effort has been wasted and money uselessly expended in fool¬ 
ish attempts at prophylaxis by individuals possessing a very super¬ 
ficial knowledge of either the parasites causing the disease or the 
insects transmitting the infection, and most of the unfavorable re¬ 
ports regarding various methods of prophylaxis, if carefully studied, 
will be found to be based upon insufficient evidence furnished by 
those unacquainted with the real facts regarding the etiology of 
malaria. 
A knowledge of the morphology and life cycle of the parasites 
causing malaria and of the mosquitoes transmitting the disease is 
