IMPORTANCE OF ALKALIES. 139 



plants richest hi sugar and in starch are no less distinguished for 

 their quantity of alkaline bases and of organic acids. 



As we find sugar and starch accompanied by salts of an or- 

 ganic acid ; and as experience proves that a deficiency of alka- 

 lies causes a deficient formation of woody fibre, sugar, and starch ; 

 and that, on the contrary, a luxuriant growth is the consequence 

 of their abundant supply ; it is obvious that the object of culture, 

 viz. a maximum of crops, cannot be obtained, unless the alkalies 

 necessary for the transformation of carbonic acid into starch and 

 sugar are supplied in abundant quantity, and in a form fit for 

 assimilation by plants.* 



* The acids — malic, tartaric, citric, oxalic, &c. — are generated in the 

 organism of plants, and their carbon must be derived from carbonic acid. 



In plants these acids are found combined with potash, lime, and mag- 

 nesia, in the form of salts, the smallest particles of which, when left to 

 themselves, follow their own attractions ; this is indicated by their crys- 

 tallization. 



There is no doubt that these compounds do not possess organic life, be- 

 cause the active power observed in them is not vitality, but cohesion. 

 The same must be the case with sugar, which crystallizes in a similar man- 

 ner. 



We must presume that the smallest particles of the products formed 

 from carbonic acid are subject to the powers acting upon them in the living 

 plant, in the same way that a particle of carbonic acid is ; that, therefore, 

 the carbon of oxalic acid, tartaric acid, &c, must possess the power of 

 passing into a constituent of an organ endowed with life. 



The conversion of organic acids into organs may be followed with ease. 



If we suppose that 12 equivalents of carbonic acid, in the presence of a 

 base, and by the action of light, loses the fourth part of its oxygen, in con- 

 sequence of the action of vitality upon its elements, then oxalic acid would 

 be produced. In its anhydrous state, we cannot conceive it to be formed 

 from carbonic acid in any other way. 



C i 2 2 4 — 8 =C i a Oi 8=6 Eq. anhydrous oxalic acid. 



Oxalic acid does not exist in an anhydrous state. Hydrated oxalic acid 

 contains one equivalent of water; the oxalates of potash, lime, and mag 

 nesia also contain water. Hydrated oxalic acid consists of — 



C i 2 Oi 8 +H 6 6 =C 12 H 6 2 4=6 Eq. hydrated oxalic acid. 



From this it may be observed that carbonic acid and hydrated oxalic acid 

 contain the same quantity of oxygen. We can, therefore, suppose that 

 hydrated oxalic acid has been formed from carbonic acid, to which a cer- 

 tain amount of hydrogen has been added. 



P.y the continued action of the same agents a new quantity of oxygen 

 might become separated from the carbonic ocid. in which case tartaric acid 



