142 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



consideration of the quantity of nitrogen contained in a whole crop, will 

 satisfy any one that though small in comparative amount, it performs its 

 share of importance in reference to vegetable production. Two tons of 

 hay growing upon an acre of land will contain sixty pounds of iiitrogen. 

 A cow will eat twenty-six and a half pounds of hay in a day, and will 

 evacuate thirteen pounds of solids, containing onl}' 3.02 of nitrogen. The 

 hay contained 1.66, showing that more than twice the ainDunt of nitrogen 

 contained in the hay consumed was voided. A milch cow cannot be 

 fattened by giving milk, because the nitrogen escapes in her milk. The 

 value of all escrementitious substances depends to a certain extent upon 

 the food given to the animal, and if it is fed upon green food during the 

 summer in confinement, it will possess more than twice the strength of 

 that derived from a stall-fed animal in the winter season. Ten loads of 

 manure frum an animal fed on oil cake, is worth twenty loads derived from 

 an animal fed on straw, hay, &c. How is it that the dung and urine are 

 richer in azote, or nitrogen, than the food from which they are formed ? 

 The question is readily answered. The largest proportion of anj' vcgeta- 

 table is principally carbon and woody fibre. A cow lives chiefly upon 

 vegetables, and discharges from her lungs in the act of breatiiing, a large 

 percentage of the carbon her food contained, consequently that left in the 

 system to be thrt)wn off by the kidneys ccmtains a large qiiantity of nitro- 

 gen, which could feebly be supplied to the soil from rain water falling 

 from the clouds. All the nitrogen contained in the food beyond the require- 

 ments of the animal's system, is thrown off principally in the urine. In 

 the vegetable matters consumed by the cow, the carbon was to the nitro- 

 gen as nine to one ; but after the lungs hare performed their duty the 

 proportion is only two to one. From the residue, ricli in nitrogen, the 

 several parts of the animal body are built up. AVhen a cow dies her ani- 

 mal substances resolve organized forms into elementary constituents, and 

 the horrible effluvia disengaged during the process, points out to the farmer 

 the propriety of covering them with soil, where they may readily become 

 the food of vegetables. If such organized substances are permitted to 

 putrefy in the open air the process becomes noxious ; but beneath llie sur- 

 face of the earth their sulphuretted gases soon become the constituent of 

 a rose's perfume, and fill the air with the most delicious fragrance. The 

 fertility of all soils is supposed to depend upon humus, tliis is incorrect, as 

 humus is vegetable mould, the product of the decay of other plants, of 

 which water v/ill not dissolve more than the hundred thousandth part of 

 its weight. Decayed wood produces the same results. When we place in 

 our compost heaps vegetable matter, it undergoes first fermentation, and 

 then putrefaction. Decaying roots, stalks and grass decompose in a man- 

 ner analogous to combustion. The leaves wliich fall in the forest in the 

 fall, and the spongioles of grass in a meadow, are converted into humus 

 in the same manner, which, after its formation, does not nourish plants in 

 a direct manner by being taken up in an unaltered state, but by yielding 

 a permanent source of carbonic acid gas which the roots absorb, and re- 

 ceive nourishment from during the period they are destitute of leaves, until 

 they form which, they are incapable of imbibing food from atmosphertc in- 

 fluences. The urine of animals is the moat powerful for all vegetable life, 



