58 THE PLANT. 



gen in the seed has, under these circumstances, caused 

 the generation of 56 times its own weight of unazotised 

 matter ; or, what comes to the same thing (taking the 

 amount of carbon in the latter at 44 per cent, only), the 

 decomposition of 90 times its own weight of carbonic 

 acid. 



The course of vegetation in these plants throws 

 sufficient light upon the processes going on in their or- 

 ganism ; in the first days their developement was vig- 

 ourous," afterwards languid. The first-formed leaves 

 withered after a time, and partly dropped off, fresh 

 leaves being developed in their stead, which went on in 

 the same way ; and the vegetation seemed to reach a 

 point where the newly developed parts existed at the 

 expense of the decaying portions. A French bean, 

 weighing 0*755 gramme, planted on the 10th May, had 

 by the 30th July developed 17 leaves, of which the first 

 11 were then dead and gone. The plant flowered, and 

 on the 22nd August, when nearly all the leaves had 

 dropped off, produced a single small bean, which 

 weighed 4 centigrammes, the T ^th part of the weight 

 of the seed-bean. The entire crop weighed 2*24 

 grammes, very nearly three times as much as the seed- 

 bean. In the case of a rye-plant it was very clearly 

 observed how the unfolding of every fresh leaf was at- 

 tended with the death of one of the old leaves. 



In the second series of experiments, the plants had 

 absorbed (from the air) 1*92 milligramme of nitrogen, 

 and produced 0.830 gramme more vegetable substance, 

 giving 43 milligrammes of unazotised- matter for every 

 milligramme 01 nitrogen. 



The difference in the developement of a plant in 

 pure water from that of one grown, as in Boussingault's 

 experiments, in a soil supplying the incombustible con- 

 stituents of food, is clear and unequivocal. The organs 

 first formed received in both cases their elements from 

 the seed ; in both, a certain quantity of mineral sub- 

 stances and also of soluble unazotised matter was con- 

 sumed to form cellulose in the leaves, roots, and stems ; 

 and the proportion of the unazotised to the nitrogenous 



