526 
By a latent malarial infection we understand one in which the plas- 
modia of malaria may be demonstrated to be present in the blood of an 
individual, but in which no clinical symptoms of the disease of sufficient 
gravity to attract attention are to be observed. ‘The term should not be 
confined to those instances in which no symptoms of malaria have ever 
been present, for in recurrent cases between the attacks, the disease 
is as truly latent as it is before the initial one. Under all circumstances 
the infected individual obviously is a great source of danger to others. 
It appeared probable to me in considering the malarial situation as 
presented at Camp Stotsenberg, that the natives living in the barrios 
about the post were in all likelihood the chief source of infection, for 
while, as has been stated, the sanitary conditions in the post proper were 
such as to prohibit the belief that malarial infection could originate 
there, the same could not be said of the native barrios where the breeding 
places of mosquitoes abounded and insects of the genus Anopheles were 
numerous. In these situations the conditions for the spread of the 
human infection were ideal. In order to determine how large a per- 
centage of the native population was infected, I made blood examina- 
tions whenever they could be obtained of all the natives living within 2 
miles of the post., The results proved beyond question that the origin 
of malarial infection at Camp Stotsenberg is very largely due to the 
natives living in the immediate vicinity, and that any efforts to limit 
the disease must take this condition into account. In many of the 
persons of this race, the clinical symptoms of malaria were present at the 
time of the examination. Such cases are not included in this paper, 
which treats solely of latent infection in the native. In a considerable 
number of the instances of latent infection, even in the youngest 
children, a history of previous attacks of fever could be obtained, but 
in none of then were any symptoms of malaria observed at the time 
of the examination. In all, the blood of 225 natives was examined and 
115 or 51.1 per cent were found to be infected. 
James, in his work in India, found that the percentage of natives 
infected varied very greatly in different localities, being less than 5 per 
cent in some places and as high as 86 per cent in others. The same 
condition will be found to exist in these Islands and blood examinations 
of the natives will result in giving valuable data as to the endemicity 
of malarial disease in different localities in the Philippines. This fac- 
tor should be considered and such blood examinations of the natives 
made before permanent military posts or residences are established 
in the Tropics. 
Of the 115 infections found, the tertian plasmodium was present in 29, the 
quartan in 6, and the estivo-autumnal in 77; of the latter, 73 were due to the 
tertian estivo-autumnal plasmodium and 4 to the quotidian. There were 3 
combined infections with the tertian and the tertian «stivo-autumnal plasmodium. 
