23 
2. The different parts of the same plant yield an excess of dissimilar salts: the potatoe tuber 
contains eighty-six per cent, of potash salts — the tops sixty-one per cent, of lime salts. In the same 
way, the roots, foliage and seeds of other plants give indications of an affinity for different minerals. 
Hence it follows that analyses will differ with the nature of the soil on which the plant has been 
produced, and with the part examined, or if every portion be examined with the part used in excess. 
As it is usual to publish the mere analysis without designating the soil, or variety of the plant, 
it is necessary in arriving at trustworthy conclusions to look somewhat further than this. There¬ 
fore, in reaching my position, I have kept in view two points — the natural habitat of the plant and 
the circumstances under which its produce becomes of great excellence. Thus in the analysis of 
the onion by Fourcroy and Vauquelin, lime salts predominate; Cadet found sixty-four per 
cent, of potash salts in the garlic; but I venture to place the family to which the onion belongs 
{Aspliodelce) amongst the soda plants, because it is well known that asparagus, many kinds of onion 
and other genera are indigenous to the sea coast and salt marshes, and because the Spanish onion 
which excels all others is cultivated in lands irrigated by salt water. Cruciferous plants are soda 
plants characterized by a remarkable affinity for sulphur, yet in the analyses of the ashes of turnips 
and cabbages they appear to be potash plants, that base acting as a substitute ; I arrive at the 
conclusion that they prefer soda, from the fact that cabbages and many other cruciferous plants 
delight in situations near the sea shore. A gentleman well known to this Association has recently 
shown that the grapes cultivated near the low salt plains of New-Jersey contain soda instead of 
potash salts, and are in consequence of a very inferior flavor. Another interesting case of the influ¬ 
ence of the bases on the flavor of plants exists in the case of tobacco. The French government 
agents, finding that the tobaccos from the United States had become decidedly inferior to the old 
samples, submitted specimens to the examination of M. Pelouze, who ascertained that lime salts 
predominated in the inferior specimens in the place of the potash salts obtained by Berthier. 
In determining the place of a plant in the saline groups, I have for the most part selected the 
ashes of leaves as the true guide, because, in the first place, the leaf is the important organ of vegeta¬ 
tion in which the sap is elaborated and the future growth of the plant provided for; and secondly, 
because there is reason to suspect that some part of the saline matter of the roots may be, like that 
of the bark of trees, a refuse portion. It is true, that in the case of potatoes, the leaves are not 
removed and the saline matters of the tubers only are taken from the ground, and therefore econom¬ 
ically considered this saline matter should be estimated, but the marked effects of lime in the culture 
of potatoes, on the tubers as well as the leaves, makes it evident that this base is the one that is 
essential, and that, although potash salts are given in the analysis of Sprengel, it appears to arise 
more from the mixed nature of the soil than the predilection of the plant, and the lime salts would 
