29 



material gain in weight. It appeared from these 

 experiments that — "As in the animal ovum, so in the 

 seed, the genesis of life receives its first impulse from 

 the seed, and that most plants continue for some time 

 to draw from this source a portion at least of their powers 

 of growth," 



From some more complete experiments of Boussingault, I 

 further gathered that the elements which are used up during early 

 growth are the carbon and oxygen, and to a certain extent the 

 hydrogen, of the seed. During germination the starchy portions of 

 the seed, by a species of fermentation, under the influence of warmth 

 and moisture, and also probably by the molecular action of the 

 nitrogenous germ, become changed into sugar or other soluble 

 substances, and these are slowly disintegrated and burnt by a kind 

 of respiration, and heat and other energy is developed. The most 

 important agents in assisting the processes of growth are hydro- 

 carbonaceous particles in their course of transformation, and there 

 is little doubt that the heat energy of these compounds bears some 

 important relation to active life. 



It seems probable that the oxydation of carbonaceous 

 compounds in animals has something to do, not merely with the 

 phenomena of muscular contraction, but also with many other vital 

 processes. In like manner plants, perhaps, owe not a little to the 

 same sources. It was shown by the observations detailed above 

 that the plants lost weight during growth almost equally in the 

 light and in the dark. It was thought possible, therefore, that the 

 processes of development and growth might receive their stimulus 

 not only from the direct heat and light of the sun, but also from the 

 energy lying hid in the carbonaceous compounds already stored up 

 within the seed or bulb. 



It is probable that nitrogenous substances, as in the case of 

 animal respiration, are equally necessary for the absorption of 

 oxygen. Certain albuminous substances collect in the young leaves 

 of plants, and serve as a store of material that assists both in 

 early growth and in the evolution of leaves. The proof of this 

 statement is to be found in the fact that an albuminous substance, 

 such as asparagin, is found not only in the roots of plants and in 

 their cotyledons, but also in the petioles of young leaves. Sachs, 

 however, remarks on this point, i.e., as to asparagin, that — " Its 

 physiological significance remains at present limited to Leguminosae, 

 and in them it is confined to the consumption of the reserve 

 albuminous substances." In any case, it is evident that the storage 

 of both nitrogenous and hydro-carbonaceous material does take 

 place as a preliminary to active growth. 



These conclusions might probably be extended to certain 

 stages in the more advanced life of a plant or tree, but I have no 

 observations to adduce in confirmation of this opinion. Still, when 

 we observe the manner in which the new bud is already formed 

 in deciduous trees and shrubs, even before the fall of the leaf, it 



