456 



In all these expei-iments, an augmentation of carbon was accom- 

 panied by a diminution of hydrogen ; but the proportion of the 

 change varied. 



According to the author's experiments, so far as they have gone, 

 cellular fibre is not only soluble in alkalies, but also gradually 

 changed by them into matters which approach, more and more, to 

 the composition and properties of the ulmic acid. The difference 

 between the action of alkalies and of acids consists in this : that the 

 states of transition, namely dextrine and sugar, are not produced 

 by the action of the alkalies. Cellular fibre and the incrusting mat- 

 ters, when united in the substance of the plant, resist more power- 

 fully the influence of chemical reagents, than when they are sepa- 

 rated from each other. Pay en's idea, that the incrusting matters 

 should be considered as consisting of three substances, two of which 

 are electro-negative, seems much too limited and artificial. 



The quantity of nitrogen found in these substances was much 

 too small to exercise any influence on the composition. It is the 

 youncer parts of growing plants to which nitrogen is indispensable, 

 and in which it can always be found and demonsti-ated. 



Finally, it is not improbable that there exists a whole series of 

 incrusting matters, always present in their substance, for the use of 

 the diff'erent fluids and organs of plants : a purpose for which they 

 are eminently calculated, by their great facility of transformation, 

 and by their strong tendency to attract water. 



Were we to assume the transitory existence of ulmie acid in the 

 cells, we should probably obtain wider ideas with regard to the 

 growth and decay of plants. It is well known, with respect to the 

 decay of vegetable matter, that a large quantity of hydrogen must 

 be set free during its decomposition, by means of which the foi-ma- 

 tion of ammonia in the soil is eminently favoured. 



In the converse process, that of growth, precisely the opposite 

 process — that is, combination with hydrogen — must occur. Growth 

 is thus a reduction, decay an oxidation. The ulmic acid would 

 thus be, after the formation of the primary cell fibres, the common 

 source of all the matters deposited in the cells, in all plants whicK 

 are rooted in the ground. 



If we agree to this proposition, then we do not require the de- 

 composition of water to explain the gi'owth of plants. The large 

 quantity of pectine, C^ H® 0^'', which is present in some parts of 

 so many plants, and which may be considered as the incrusting 

 matter of the cells of carrots, turnips, different kinds of fruits, &g. 



