ANALYSIS OF THE VEGETATION OF THE GRAMINEA. 587 . 
strong rotation towards the left, thus detecting the mixture of grape 
sugar, not solidified, with cane sugar, which mutually concealed each 
other before the latter was interverted. The substance exhibiting a ro- 
tation to the left, and precipitable by alcohol, experienced also the alco- 
holic fermentation by contact with yeast, this property being either 
proper to it or arising from asmall quantity of sugar which might have 
been entangled with it in the precipitation. But the effect of the fer- 
mentation was only to weaken the rotation, without altering its direction. 
Twelve days after, on the 15th of May, the ears being more deve- 
loped, but still far from flowering, the stems again presented the 
mixture of these three substances. But the proportion of cane sugar 
was increased, for it determined the resultant of the rotation in its pro- 
per direction, towards the right, before fermentation. When this sugar 
was destroyed in the extract by boiling it with sulphuric acid, the in- 
fluence of this acid changed the direction of the rotation of the sub- 
stance precipitable by alcohol, which passed from the left to the right. 
This, as M. Persoz and myself have shown, is also a property of gum. 
The extract from the ears before flowering presented characters 
very different from the extract from the stems. Neither cane nor grape 
sugar was detected in it, but only sugar of starch (suere de fécule), 
which the fermentation enfeebled without changing. Alcohol also 
produced a precipitate in it, but of a different quality to that of the 
stems, for it was not soluble in water, or only so in a very small degree ; 
and this precipitate viewed with the microscope appeared formed only 
of shreds of cellular tissue and the remains of integuments similar to 
those which cover the globules of starch, without any sensible mixture 
of pulverulent matter. These results agreed with M. Raspail’s observa- 
tions, that the pericarp of the Cerealia before fecundation is filled with 
starch ( fécule) in very small grains, the soluble matter of which is pro- 
gressively absorbed by the ovary, and serves as nourishment to it when 
the fecundation is effected. But as the extract of the ears made pre- 
viously to fecundation here presents us with sugar of starch, not with 
dextrine, it is evident that the globules of the pericarp must either con- 
tain this sugar ready formed and prepared to be absorbed by the young 
ovary, or that the globules are accompanied by a principle analogous 
to diastase, which breaks them and converts their dextrine into sugar, 
as in germination. 
After fecundation is effected the composition of the ears is greatly 
altered. On the 15th of June the young grains of rye, taken from 
the ears, contained grains of starch ready formed, which were visible 
with the microscope. They burst under the influence of sulphuric 
acid and disengaged a substance soluble in water and precipitable by 
alcohol, which is ascertained to be dextrine by the great energy of 
its rotatory power compared with its density. Sugar of starch ready 
