AND PREVENTION OF MALARIA. 231 



greatest authorities, showing ueed of drainage. We can 

 readily imagine one condition which will produce this 

 result, viz. excessive dew, which will evaporate and carry 

 a large amount of organic matter ;* others may depend on 

 the plants and animals present. The oxidation in the soil 

 may also be aided by the artificial opening of its structure, 

 but this may not always be convenient, and the demand 

 for it may be too laborious. Are we not able to imitate 

 some of the other methods taken by nature to prevent 

 infection ? 



If we add any acid to the putrid soil of which I spoke, 

 that peculiar mode of decomposition ceases ; if we add any 

 other disinfectants or antiseptics we put a stop to decom- 

 position. If we add antiseptics to the water over soil 

 containing a great variety of animalcules, and giving every 

 evidence of decomposition, we find these instantly dying ; 

 the same, of course, results with grubs, larvge, &c. Animal 

 life is arrested, and chemical action is staid or im- 

 peded according to the amount used ; but a very large 

 amount must be taken in order to show an injurious effect 

 on vegetation. In this experiment we do in reality pre- 

 vent malaria; we arrest the decomposition of substances 

 in the soil. We cannot call this a theory or a speculation; 

 it may be considered simply as a fact. The use of anti- 

 septics will arrest all animal and vegetable decomposition, 

 and where there is neither of these malaria will not arise. 

 The chemical action which goes on in a vessel containing 

 a few cubic inches will not differ if extended over a surface 

 of miles. I look on the results, therefore, as certain, viz: 

 that by the use of disinfectants malaria will be destroyed. 



The idea of the disinfection of whole districts rose out 

 of a proposal made long ago to disinfect whole cities by 

 beginning at the root of the evil, the sewers. That was 



* Since writing this an Italian friend informs me that this opinion is 

 prevalent amongst the scientific men of his country. 



