No. 244.] 409 



general ; namely, carbon, hydrogen, nitrogen, and oyxgen. These 

 elements are always present in plants, and produce by their union 

 the various proximate principles of which they consist." " Nitro- 

 gen is quite opposed in its chemical character to two bodies now 

 described, (referring to carbon and hydrogen.) Its principal charac- 

 teristic is an indifference to all other substances, and an apparent 

 reluctance to enter into combination with them. When forced by 

 peculiar circumstances to do so, it seems to remain in the corabina- 

 ticn by a " vis merticB,'" and slight forces effect the disunion of these 

 feeble compounds. Yet nitrogen is an invariable constituent of 

 plants, and during their life is subject to the control of vital powers. 

 But when the mysterious principle of life has ceased to exercise its 

 influence, this element resumes its chemical character, and materially 

 assists in promoting the decay of vegetable matter by escaping from 

 the compound, of which it formed a constituent." Nitrogen is an 

 element of vegetable albumen and gluten ; it is a constituent of the 

 acid, and what are termed " the indifferent substances" of plants as 

 well as of those peculiar vegetable compounds which possess all the 

 properties of metallic oxides, and are known as " organic base." 

 Estimated by its proportional weight, nitrogen forms only a very 

 small part of plants, but it is never entirely absent from any part of 

 them ; even when it does not absolutely enter in the composition of 

 a particular part or organ, it is always to be found in the fluid 

 which pervades it." It follows, from the facts thus described, that 

 the development of a plant requires the presence, first, of substances 

 containing carbon and nitrogen, and capable of yielding these ele- 

 ments to the growing organism ; secondly, of water, and its ele- 

 ments, and lastly, of a soil to furnish the inorganic matters, which 

 are likewise essential to vegetable life. 



Now, in the residuum of animal manures, after the escape of hy- 

 drogen and oxygen, we must have alone carbon and hydrogen, as 

 the remaining original constituents of vegetable vitality ; we, there- 

 fore, furthermore, only require the fixation or retention of the volatile 

 alkali, ammon'a, (formed by the union of hydrogen and nitrogen,) 

 the value of which, to vegetable life is essential. In the case of Do- 

 yer's agent for the deodorization of animal effeta or ordine, the ni- 

 trate of ammonia is produced, and the alkali rendered less volatile 

 by its additional equivalent of nitrogen, remains longer the source of 

 fertilization, the carbonic acid being, from its own density, one-half 

 heavier than atmospheric air, preserved in its original power, as con- 

 tained in the excretion of animal life, otherwise, than that lost 

 through respiration. 



