owe 
_ insoluble salts exist in the tissues of plants. 
-general agreement in the composition of their ashes, while p! 
_ and the penny cress, in zinc soils.4 In the leaves of the 
: essential inorganic constituents will depend upon their 
to the changes in the vegetable cell. a 
Ward to the leaves, the largest percentage being found 1 
_ younger portions of the growing plant, and I have observed 
Same principle on a more general scale running throug” 
` | entire plant kingdom, for the largest ash-percentages 
724 Comparative Chemistry of Higher and Lower Plants, 
These ash-ingredients are usually present in each plantei 
in the cell-wall, imbedded in the cellulose and partly in the cot 
tents of the cell. The salts of the alkaline metals, sulphatsy 
chlorides of magnesium and calcium, also soluble silicic adi 
as in Equisetum hiemale, occur in solution in the cell-sap, "i 
The differences in the composition of the ash of plants shor , 
that each plant is endowed with a specific absorbent capacity ; 
thus a gramineous plant? is able to withdraw relatively lag 
quantities of silica from the soil than a leguminous plant. be | 
latter can only do so to a very slight extent. $ 
he absorbent capacities of allied species are very differ | 
Again, individuals of the same species yield different asi” 
stituents, depending upon their vigor, and at different periods 0 
growth the ash-composition varies, In a summary of ep 
mental results it has been stated that? “similar kinds of peg 
and especially the same parts of similar plants, exhibit = 
which are unlike in their botanical characters are also unlike” 
the proportions of their fixed ingredients.” au 
-ertain marked varieties of plants appear to be peculiar * 
and developed by certain soils, as the violet, var. cam 
of their use or harmfulness to the plant, but the absorpti 
< othe ash-constituents of a plant increase from the roo? 
co 
among those plants lower in the evolutionary scale, w 
; Estee, Ber. d. deut, chem., Ges. xi. 2 Wolff, Aschenana’j 
Uo Crops Grow, by S. W. Johnson, London, p. 145- 3 
: raum and Risse, Sachs, Exp. Physiologie, 153. 
Amer, Phil. Soc, Trans., H. C. De S. Abbott. 
