SAP. 



Potasb 14-10 Oxygen. 



Soda 20-70 " —^ «.io oi «-r,T„»„ 



Lime 12.30 « 3.4^ )► 12. 84 oxygen. 



Magnesia 14.35 " 



51.45 



In this ash the bases belonging to the inorganic salts contain 1.37 

 of oxygen. The oxygen of the bases of the carbonates, or in other 

 words of the bases which formed organic salts in the tree, therefore, 

 becomes 11.47. The numbers 9.01 and 8.95 on the one hand, and 

 11.62 and 11.47 on the other, which represent the quantity of oxy- 

 gen of the whole of the bases in the ashes obtained from plants of 

 the same species, differ so little, that they may be considered as 

 identical. 



Accurate analyses of ashes of plants of the same species grown 

 in soils of different kinds, will determine, says Prof. Liebig, whether 

 the fact, deduced from the composition of the ashes of the pine and 

 fir-tree, constitutes a definitive law.* 



Be this as it may, the utility of alkalies in vegetation cannot be 

 a matter of doubt ; many usages in agriculture prove it in the 

 clearest manner; and, according to M. Liebig, the fact of the forma- 

 tion of the organic alkaloides in plants aflfords an additional proof 

 of it. M. Liebig thinks that the organic alkalies have a particular 

 tendency to form in the absence of mineral bases ; thus potatoes 

 which germinate in cellars, under conditions where the soil cannot 

 supply them with potash, soda, or lime, develop an organic alkali, 

 solanine, which is not found in the tubers of this vegetable as usually 

 cultivated. t In the cinchonas, quinine and cinchonine are combined 

 with quinic acid ; but there is frequently found quinate of lime also. 

 According to the same chemist, the latter base holds the place of a 

 vegetable alkali in the organism ; the more prevalent it is in the soil, 

 the less rich will the cinchona plant be in quinine and cinchonine.;^ 

 These ingenious views certainly deserve the careful attention of 

 physiologists ; they are calculated to add new interest to the study 

 of the chemical constitution of the ashes of vegetables. 



The inorganic substances contained in vegetables evidently come 

 from the soil. By growing seeds, as M. Lassaigne did, in flowers 

 of sulphur, moistened with distilled water, the plant produced con- 

 tained neither more nor less saline and earthy matter than was origi- 

 nally present in the seed. 



The water absorbed by the roots, then, becomes charged during 

 its stay in the ground with the various soluble substances which 

 may be met with there, and which generally contribute to its fer- 

 tility ; sucV. especially are the salts derived from decomposed organic 

 substances. Water charged with small quantities of the soluble 

 substances diffused through the soil, constitutes the ascending sap. 

 When it has penetrated the plant, immediately after its passage by 

 Ihe spongi.les of the roots, perhaps even while traversing these 



* Liebig, Chimie Organiqne, Introduction, p. cxi. 

 t Liebig, idem. p. cxiv. 

 i Liebig, idem. 



A* 



