1887, | BOTANICAL GAZETTE. 37 
It seems to me that there is one fact that the physiologists 
forget, v7z., that starch is not always insoluble. In my ex- 
aminations of sorghum juices I have never failed to find 
soluble starch when I looked for it. The existence of bodies 
when first formed in the soluble state, which when once 
made solid become insoluble, is not unknown. Certain forms 
of silica are illustrations of this. It seems much more reas- 
onable to suppose that in the case of the sorghum for instance 
the starch which appears in the seed is partly transferred 
directly from the soluble nascent state to the seat of its final 
deposition. This, indeed, is hardly a theory in the light of 
the fact mentioned above: that the sap of the plant always 
contains soluble starch. ; 
ed by the commonly accepted theory that the starch in 
the grain of cereals, etc., was formed from sugar, a few years 
ago some experiments were made to increase the sucrose in 
sorghum by cutting away the seed heads as they appeared 
and thus preventing the formation of starch. Two or three 
analyses were made and the results showed a large increase 
in the sucrose in those plants in which the formation of starch 
had been prevented. 
In 1885 I conducted some experiments on a large scale. 
About two acres of a sorghum field were selected. In each 
alternate row of the growing cane the seed heads were re- 
moved as they appeared. Numerous analyses were made 
of the canes from both kinds of rows. The result showed 
most conclusively that no marked increase of sucrose was 
hoticed by reason of the prevention of the deposition of 
Starch. It is far more simple to suppose that the sucrose 
which we find in sorghum is produced directly by the de- 
composition of protoplasm in presence of carbonic acid, 
provoked by the katalytic action of the chlorophyll cell. At 
any rate there is no sort of evidence that it is ever made from 
starch and no physiologist has ever invented any hypothetical 
Saccharoplast to account for such a transformation. : 
This subject of the origin of sucrose is of great interest 
but I have not yet finished my experimental studies of it and 
So will not pursue it further at present. 
