330 QUARTERLY JOURNAL. 



version of the carbon of the tartaric acid into that principle of 

 malic acid which succeeds to it, a transformation not easily involv- 

 ed in doubt, as much as we have to attribute it to the metamor- 

 phosis of those acids into sugar. 



The opinion that a plant assimilates carbonic acid, that this car- 

 bonic acid takes in its organism the forms of tartaric, racemic, and 

 citric acids, only to be finally converted into carbonic acid ; this 

 opinion, I say, cannot be reasonably sustained. 



If this mode of view relative to the part which organic acids 

 take in the formation of sugar be confirmed, it should have the 

 same value relative to the formation of all the other non-nitroge- 

 nous substances of similar composition ; the formation of starch, 

 prctine, and gum, is not, therefore, immediately produced, without 

 transition, by the carbon of the carbonic acid, and the elements oi 

 water ; but a gradual transformation is operated in consequence ol 

 the production of coml^inations which become, by degrees, more 

 poor in oxygen, and richer in hydrogen. The formation of oil o: 

 turpentine cannot be represented without the production of analo- 

 gous intermediate bodies. 



But if the organic combinations, rich in oxygen, the acids, an 

 the intermedia of the production of those which contain less oxy 

 gen, sugar, starch, &c., it is clear, that in cultivating plants, i) 

 which the acids are rarely in the free state, but in which they ordi 

 narily exist under the form of salts, the alkalies and the alkalin 

 bases should be regarded as the conditions of the production of th 

 non-nitrogenous principles. Without the presence of these base: 

 an organic acid may, perhaps, be formed ; but, without the acic 

 neither sugar, starch, gum, nor pectine, can be formed in the orgc 

 nism of these plants. In the fruits and seeds, in which the orga 

 nic acids are free, that is to say, not in the state of salts, such i 

 citric acid in lemons, oxalic acid in chick-peas, sugar is not form 

 ed. Sugar, gum, and starch, are produced only in the plants i 

 which the acids are found combined with bases, which are met wit 

 in plants. 



Whatever may be the value which may be accorded to th 

 opinion concerning the part performed by alkaline bases in ll: 

 vital act of vegetables, the positive fact that, in young shoots, th 

 leaves and buds which are developed, consequently in the parts ( 

 the plants in which the faculty of assimilation is observed in i 

 greatest force, the proportion of alkaline bases is most considerab 

 that the vegetables most rich in starch, are not less distinguishej 

 by their richness in alkaline bases, and in organic acids ; thisobseil 

 vation, I say, cannot, on account of this view, lose its value i 

 rural economy. 



If we find sugar and starch accompanied by salts, formed t 

 organic acids, and if experience demonstrates that, without alkjj 

 line bases, all the development of the plant, the formation of sugaii 



