MALARIA. 235 



yet able positively to affix certain general 

 characters to them. The poison infused into the 

 air appears to be ponderous : this is shown by 

 the fact that it accumulates near the earth, since 

 it is safer to sleep on the top of a house than at 

 the bottom ; persons occupying the lower stories 

 have been attacked with ague, while those on 

 the upper have escaped the complaint. It does 

 not appear to be altogether gaseous, for the 

 Italians are in the habit of wearing gauze veils 

 as an efficient protection from it, the infiltered air 

 being thus divested, as they state, of its injurious 

 powers. It is invisible, inodorous, and gives 

 no indication of its presence by any chemical 

 quality whatsoever. A variety of conjectures 

 have been made upon its nature, and some have 

 even supposed that it consisted of minute ani- 

 malcules. Probably one of the most happy of 

 the explanations given is that which refers it 

 to the existence in the atmosphere of certain 

 minute organic particles buoyant with every 

 wind, coming into existence as a product of the 

 putrefactive process in vegetation, and capable 

 when inhaled by the lungs and received thus 

 into the circulation, of inducing that peculiar 

 form of disease by which its effects are character- 

 ised. But after all it must be confessed, the ex- 

 planation itself wants to be explained. 



The subject of Epidemic Disorders that is, 



