234 THE CHEMISTRY OF CREATION. 



Italy, the inhabitants attribute it to the malaria, 

 or bad air. 



No doubt they are correct. The air of such 

 districts contains something in addition to those 

 ingredients which in the last chapter we found 

 to constitute the composition of the atmosphere 

 generally. Nitrogen, oxygen, carbonic acid, 

 carburetted hydrogen, and ammonia, although 

 representing the ordinary ingredients of the 

 atmosphere, are not, therefore, its only con- 

 stituents in particular cases. Dr. Prout says, 

 " The atmosphere may be conceived to contain a 

 little of everything that is capable of assuming 

 the gaseous form." We shall learn, however, 

 further on, that there are active chemical pro- 

 cesses taking place in the air itself, which in a 

 short time remove such "occasional ingredients" 

 from its contents. 



What is known upon the chemistry of Malaria 

 at present is but unsatisfactory. When vege- 

 table matter is left to rot, with a limited supply 

 of water, and at an elevated temperature, it 

 begins to give rise to certain products of its 

 decomposition which escape into the air, and 

 constitute what is called malaria. Chemistry 

 is in great ignorance upon the nature of these 

 products; but the most curious facts exist, by 

 which, although we can neither determine their 

 nature nor analyse their constitution, we are 



