96 PEOPAGATIOK OF PLANTS. 



no one in the management of plants. All practical cul- 

 tivators of plants recognize the great value of carbonar 

 ceous matter, not only as found spread over the surface 

 of the earth in forests, prairies and plains, but in the 

 manures applied to soils from which it has been exhausted 

 by long cultivation or otherwise. It is not denied, how- 

 ever, that plants do absorb carbonic acid gas through 

 their twigs, buds, leaves, and other appendages ; in fact, 

 as they take in moisture through these parts, other nu- 

 trients must also pass in combination with it, as well as 

 carbonic acid gas, but in infintesimal quantities compared 

 ■with the amount absorbed by the roots. 



In this respect plants do not differ greatly from ani- 

 mals, for it is well known that nutrients and poisons may 

 be conveyed by air to the blood through the lungs, or 

 they may be thrown directly into the system by hypo- 

 dermic injections through the skin ; that a starving man 

 would live longer in an atmosphere laden with the fumes 

 of cooking meat than in one from which such fumes 

 were entirely absent ; still, few of us would care to take 

 all our beefsteak in this way. 



I have been prompted to refer to this subject of the 

 sources of carbon in plants somewhat at length, because 

 it has of late become quite a habit among writers on agri- 

 cultural and horticultural topics to ignoi'e the value of 

 carbonaceous matter in the soil, and some go so far as to 

 doubt the value of ammonia and other sources of nitro- 

 gen ; in fact, they would lead us to believe that with air 

 and water, and a few broken rocks for an anchorage, the 

 husbandman will be enabled to produce the most luxu- 

 riant growth in plants of all kinds. But it will be well 

 for the cultivators of plants to continue the practice of 

 applying liberal quantities of carbonaceous and nitro- 

 genous manures to their soils, trusting to these to supply 

 the greater part of the nutrients, and" these through the 

 roots of plants, or by placing the food where it wiU be 

 most likely to be utilized. 



