138 MASSACHUSETTS AGRICULTURE. 



of known substances, constituting one-ninth part of the weight 

 of water, and entering but slightly into the composition of ani- 

 mal and vegetable bodies ; and nitrogen, constituting seventy- 

 nine per cent, of the bulk of the atmosphere, and forming a part 

 of most animal and vegetable substances. Plants, then, being 

 composed chiefly of carbon, oxygen, hydrogen, and nitrogen, 

 must be fed with these in due proportion in order to produce 

 a vigorous growth and an abundant harvest in return for the 

 labor, skill, and care of the husbandman. The carbon is de- 

 rived from carbonic acid, oxygen from the atmosphere, hy- 

 drogen from the decomposition of water, and nitrogen from 

 ammonia, absorbed by water, and received by the plants through 

 their rootlets. Earthy particles and salts are always present 

 in plants. In composting manures, the aim of him who engages 

 in it is, or should be, to provide food for plants by furnish- 

 ing them with carbon and ammonia, materials found in great 

 abundance in the decomposition of both vegetable and animal 

 matter. 



The food of man and his domestic animals depends, chiefly, 

 both as to quantity and quality, upon his skill and industry, as 

 manifested in his cooperation with Nature in the production of 

 such vegetables as are needed for growth and nutrition in the 

 animal kingdom, such as are either immediately or mediately 

 dependent thereon. 



It is a law of Nature, that the higher the grade of the animal, 

 and the more complicated its organism, the greater the neces- 

 sity of a corresponding' degree of food. Man is the noblest 

 creature that God has made on the earth, and, consequently, 

 has the most complicated and highly-wrought organization of 

 animated nature. How, or upon what, shall man subsist ? What 

 does the best economy of his system require ? A critical, 

 c cmical analysis of his body, fed and nourished under the 

 direction of knowledge reflected upon the subject by the light 

 of physiology, will show its composition, and, therefore, de- 

 monstrate what elements the soil needs to produce bodily nutri- 

 tion. Those elements will be found most important as fertil- 

 izers of the soil that enter most largely into the growth and 

 maintenance of the human body. Man, in his present state, is 

 both an hcrbiverous and carnivcrous auimal, being composed 



