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appeared from England. This would naturally reduce the 
number of infected individuals and thus lessen the chance 
of the Anopheles becoming infected. 
" (c) It is possible that the use of quinine has reduced 
the chances of infecting the Anopheles through checking 
the development of the parasites in the blood of subjects 
affected with ague. 
" Of these, the first-mentioned cause seems to have been chiefly 
operative. 
" 6. Since the geographical distribution of Anopheles in England 
is wider than the former distribution of ague in this 
country, we are forced to conclude that it is not a matter 
of the geographical distribution of Anopheles as much as 
of their numerical distribution. 
" 7. Our observations having proved the existence of Anopheles 
in non-malarious districts, we believe that they will explain 
the occasional occurrence of ague in out-of-the-way 
places, without making it necessary to assume that 
malaria-bearing mosquitoes have been freshly-imported, 
for, given suitable conditions of temperature and the 
requisite number of Anopheles, a. malarious subject coming 
from other parts might well infect the local insects, which 
in turn would spread the infection to healthy persons. 
