COUESE OF VEGETATION IN PLANTS. 4,5 



thing (taking tlie amoiuit of carbon in the hitter 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 organism ; in 

 the first days their developement was vigorous, 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 deve- 

 loped 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 liad dropped off, produced a 

 single small bean, which weighed 4 centigrammes, the 

 -J-gth 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 attended with the death of one of the old leaves. 



In the second series of experiments, the plants had 

 absorbed (fi^om the air) 1-92 milligramme of nitrogen, 

 and produced 0-830 gramme more vegetable substance, 

 giving 43 miUigrammes of unazotised matter for every 

 milhgramme of nitrogen. 



The difference in the developement of a plant in pure 

 water fi'om that of one grown, as in Boussingault's ex- 

 periments, in a soil supplying the incombustible consti- 

 tuents 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 substances 

 and also of soluble unazotised matter was consumed to 



