THE SOIL. 391 



their wants, and of the most nutritious character ; but, beyond this 

 gigantic experiment, to which few can aspire, nothing certainly is 

 to be hoped for. The farmer s whole business, as far as cultiva 

 tion is concerned, lies with the soil ; and upon the soil, and the 

 skill and intelligence with which he manages it, must depend 

 entirely his success. The notion, that plants receive a large por 

 tion of their nourishment through their leaves, although some 

 experiments, in my opinion riot sufficiently decisive to determine 

 the question, seem to favor it, appears to me about as probable as 

 that animals receive a large portion of their nourishment through 

 their lungs. If they absorb carbon and discharge oxygen by day, 

 they reverse the process, and absorb the oxygen of the atmos 

 phere, and discharge the carbon, by night ; and what portion of 

 the latter in this way is assimilated, and made to form a part of 

 the plant, (as far as I can understand the experiments which have 

 been made,) does not as yet seem to be determined. I know the 

 confidence with which this is affirmed, and, as a philosophical 

 fact, I admit that it is of great interest and extremely worthy of 

 inquiry. A friend, a few days since, said to me that he was con 

 scious, when immersed in water, of absorbing considerable water 

 by means of the pores of the skin, and wished me to believe it. 

 With great respect both for his intelligence and honesty, I still 

 remain skeptical. What may be the case after death, when de 

 composition has commenced, is an entirely different matter. At 

 present, I believe that the only way in which the food, by which 

 the body is nourished, is received, is by the mouth ; always except 

 ing the case of the soldier at Washington, so fully reported in the 

 medical journals, who had a hole in his stomach, by which, in 

 order to watch the process of digestion, food was supplied, as a 

 servant puts away cold meat in a cupboard. The fact is un 

 doubted that plants by day absorb carbonic acid and exhale oxy 

 gen, and that by night the process is reversed, and they inhale 

 oxygen and expel carbonic acid ; but it does not seem so well 

 established that in this way they obtain the carbon which is 

 assimilated in their organism. At least, the supposition is so 

 little favored by analogy, that I hope it may be lawful still to 

 doubt. 



That the atmosphere contributes essentially to vegetation that 

 plants derive much of their nourishment and substance from the 

 air, as I have already remarked, does not admit of a question : 



