260 Dr. Dauseny on the Degree of Selection exercised by Plants, with regard 
I may remark, that all the four samples of barley-straw, which had been 
watered with the strontian solution, were examined with care in the hope of 
detecting in them the presence of that earth; but the earthy matter obtained 
from those planted in sea-sand and in sulphur presented not even a trace of 
it, that from sulphate of strontian only 0°3 of a grain, that from Carrara 
marble only 0"4,—an amount beyond comparison smaller than what would 
have been present had it been secreted with the same readiness as a calcareous 
salt would have been. Yet that the presence of nitrate of strontian did in some 
measure contribute to the growth of the plant may be inferred by comparing 
the amount of barley-straw obtained from the flowers of sulphur watered with 
that solution, and that from the same matrix moistened merely with distilled 
water. 
In the first case, the barley-straw weighed 78 grains, and the ashes derived 
from it 7 ; whilst in the second, that from an equal amount would have yielded 
48 grains, and its ashes only 3 grains. 
The same year a similar train of experiment was pursued with the Lotus 
tetragonolobus, or Winged Pea Trefoil. | 
Six hundred grains of the seeds of this plant were sown in each of the boxes 
employed in the foregoing experiments. They were moistened from time to 
time, as before, with water containing two ounces of nitrate of strontian to the 
ten gallons, and they were not cut down until the whole of this water had 
been expended upon them. 
In order the better to arrive at an approximation to the actual increase of 
solid matter obtained during the process of their vegetation, the plants were 
taken up by their roots, and the adhering earthy matter carefully detached ; 
but lest this should have been incompletely effected, the stems and other parts 
as the plant was taken up before it could be expected, in the natural course of things, to have begun to 
draw upon external sources for a supply of earthy matter. It is well known that the albumen of 
the seed is expressly provided for the nutriment of the infant plant; hence, the first effort of germina- 
tion is to produce nothing more than an evolution of matter previously existing in the seed, and it is 
only in the future progress of the plant towards maturity, after this internal supply has been exhausted, 
that we can hope to trace, if at all, any increase of earthy or alkaline matter. Now M. Laissaigne's 
experiment was stopped at the end of fifteen days, a period too short to allow of much accession of 
earthy matter from without to have taken place.—See Richard's Elements of Botany, English Trans- 
lation by Dr. Clinton, p. 213. 
