638 APPENDIX. 



much quinine is given, the plasm odia can readily be 

 found, usually in considerable numbers. In some very 

 mild initial paroxysms the plasm odia may be difficult 

 to find. In aestivo-auturnnal 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, oir 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 amoebae are con- 



