10 
PROPHYLAXIS OF MALARIA. 
eradication of these fevers in every locality. Unfortunately, we 
must admit that in practice we can only hope for a partial success 
if we depend upon one method of prophylaxis alone, and it is gen¬ 
erally necessary to combine methods looking to the destruction of 
mosquitoes, the protection of man from the bites of these insects, and 
the destruction of the malaria plasmodia. 
That methods based upon the discoveries of Laveran and Koss, 
when properly applied, are successful has been proven by numerous 
sanitarians. The success achieved by Gen. Gorgas and Col. Kean, 
of the Medical Corps, in Habana; of Gen. Gorgas in the Canal Zone; 
of Celli in Italy; of Watson in the Federated Malay States; and of 
the Sergents in Algeria in the prevention of malaria has demon¬ 
strated for all time the wonderful value of prophylactic measures 
against these infections, and there is no more striking illustration 
of what may be expected from intelligent prophylaxis than is shown 
in Chart No. I, giving the malarial rates in the Canal Zone since 
1906 to 1913. As will be noted, during 1906 nearly T per cent of the 
entire working force on the canal entered hospital each month suf¬ 
fering from malarial infections, while in 1912 less than 1 per cent 
per month entered hospital from these infections. 
In the Army there has been a gradual and continued reduction in 
the number of cases of malaria since 1898, as shown by Chart No. II. 
It should be understood, however, that the enormous number of 
admissions from malarial fevers in 1898, 1899, and even in 1900, as 
shown in this chart, can not be taken as representing the actual 
facts, for it is well known that a very large percentage of the cases 
of typhoid fever occurring during these years, and especially during 
1898 and 1899, were diagnosed as remittent malarial fever and so 
entered upon the records. However, if Ave accept the year 1901 
as representing accurate statistics of this disease, it will be noted 
that the admission rate for all American troops, serving both at 
home and in our tropical possessions, has been reduced from 365.39 
per 1,000, the rate for 1901, to 24.75 per 1,000, the rate for 1913. 
The noneffective rate from malarial infections, the best index 
we possess of the influence of the disease upon the efficiency of the 
Army, has likewise fallen greatly. This rate for all American 
troops, as shown in Chart III, serving both at home and abroad, 
Avas 4.46 in 1903, while in 1913 it was only 0.53, the loAvest noneffec¬ 
tive rate from these feA^ers since 1898. 
In the troops serving in the United States the reduction in 
malaria, as would be expected, has been more marked than in the 
Philippines. In Chart No. IV is given the admission and non- 
effective rates for these fevers since 1904, and it will be noted that 
there has been a steady decrease in both rates, until in 1913 we 
