THE WASTE AND CONSERVATION OF PLANT FOOD. 



235 



Warington says in speaking of this phenomenon : 



"That a vegetable organism shonld be able to acquire from the air 



the whole of the nitrogen which it needs is S^f ^i^J^ ^f/f J/^m^^^^^^^^ 

 and is an extraordinary fact both to the physiologist and the chemist. 



The fact that a few million years may supervene before the particle 

 that is carried off to-day as waste may return to organic life shows 

 the patience rather than the wastefulness of nature. 



As a result of this general review of the migrations of plant food, the 

 reassuring conclusion is reached that there is no danger whatever of the 

 nltimate consumption or waste of the materials on which plants live. 

 Circumscribed localities, through carelessness or ignorance, where 

 once luxuriant crops grew, may become sterile, but the great source ot 

 supply is not exhausted. In fact, as the rocks decay and nitrifying 

 oro-anisms increase, the total store of plant food at the disposal of vege- 

 tation may continue to grow. When we join with this the fact that the 

 skill of man in growing crops is rapidly increasing, we find no danger 

 ahead in respect of the quantity of human food which may be produced. 



Only the novelist might be able, by the aid of an unfettered imagina- 

 tion, to say how many human beings the United States alone will be 

 able to feed in comfort. With the aid of scientific agriculture, with the 

 help of the agricultural chemist, we may safely say that a thousand 

 million people will not so crowd our means of subsistence as to make 

 •Malthus more than a pleasing theorist. As I pointed out in my vice- 

 presidential address at Buffalo, the death of humanity is not to come 

 from starvation but from freezing, and many a geologic epoch will come 

 and go before this planet dies of cold. 



1 Chem. News, October 13, 1893, page 170. 



