638 APPENDIX. 
much quinine is given, the plasmodia can readily be 
found, usually in considerable numbers. In some very 
mild initial paroxysms the plasmodia may be difficult 
to find. In estivo-autumnal malaria, while quinine is 
being administered, there may be no organisms during 
the period between the second and fourth day, but on 
the fourth or fifth day the crescents almost always make 
their appearance, notwithstanding the use of quinine 
(Ewing). 
Mode of Infection. It is generally acknowledged 
that the most common mode of infection in malaria 
is through the air. Whether the disease may be 
directly conveyed by water has been much disputed. 
Many favor the view, but experimental evidence is 
distinctly against it. Persons have been allowed to 
drink water from the Pontine marshes without ill 
effects, and in Bacelli’s clinic at Rome experiments 
were made in thirty cases with water from malarial 
districts without a single positive result. Grassi could 
not produce the disease with dew from malarial regions 
or by allowing healthy men to drink blood from mala- 
rial patients. We may therefore assume that malarial 
infection is not produced, as a rule, by way of the in- 
testines. Numerous experiments have shown, on the 
contrary, that the infection may be induced by subcu- 
taneous inoculation. It is quite conceivable, therefore, 
that under natural conditions malarial infection may be 
produced by way of the skin, and possibly by the bites 
of insects. This is all the more probable, as certain 
varieties of mosquitoes, in malarial regions, have been 
found to be laden with the plasmodia. In another wide- 
spread disease produced by blood parasites—Texas fever 
in cattle—it has been shown that the amcebe are con- 
