ON THE CARBOHYDRATES OF CEREAL STRAWS. 2638 
habit’ were those of acid hydrolysis, and the problem resolved itself into 
an investigation of the most favourable conditions of selective attack by 
suitable acids. To simplify the problem we confined ourselves at first to 
the celluloses proper, isolated from the straws by the usual methods of 
treatment. 
The results of these investigations, which occupied us for six months, 
are recorded in a paper communicated to the Chemical Society, and 
published in the Journal for June 1896, p. 804. 
The method of attack employed consisted in digesting the celluloses 
for fifteen minutes in a 1 per cent. solution of sulphuric acid, at a 
temperature of 140-150° C. 
By this method we are enabled to separate the furfuroids almost 
quantitatively, and in a condition of molecular simplicity. As obtained 
from the celluloses, the reactions cf these compounds are those of a pentose 
O 
monoformal CoHO5€ OH. It does not follow, however, that when 
O 
isolated directly from the straws themselves, or from the stems in earlier 
periods of growth, the whole of the furfuroids will be found to have this 
constitution. Our subsequent work has been directed especially to this 
question. The problem involved may be briefly stated as follows : 
The pentoses are formed in the plant from the hexoses. In this 
process a terminal CH,OH group is eliminated. The mechanism of the 
change, which must involve an oxidation to CO, is probably one of re- 
arrangement, and not an oxidation from without. The pentose monoformal 
represents the intermediate term of the series. The tendency to the 
transformation must belong either to the special configuration of the 
hexose, or to the special mode of aggregation of the molecules in the form 
of a tissue substance or cellulose. Assuming the former, it may result 
from these investigations that one of the hexoses as yet unknown will be 
found to have its terminal CH,OH group ina specially sensitive condition 
by reason of exceptional configuration, 7.e., disposition of its alcoholic OH 
groups. It is noteworthy, in fact, that the four hexoses, as yet unknown, 
are of configurations suggesting a wider divergence from the better known 
carbohydrates than these show amongst themselves. Thus: 
By (eth (EO 
CH,OH—C C C C—COH ; and its Antilogue 
OH OH OH 
and 
EG) oekic 2) Es «HL 
CH,OH—C C C C—COH ; and its Antilogue 
OH) OF). OH. «OH 
Tt is, indeed, not improbable that a special equilibrium might 
characterise hexoses of this configuration, either in the isolated condi- 
tion, or in the form of molecular aggregates. This is, of course, a speculative 
hypothesis. 
Actually we do find that the furfuroids are obtained in varying con- 
ditions, and an important diagnosis is their greater or lesser susceptibility 
to alcoholic fermentation by yeast. 
Thus, as isolated by acid hydrolysis at high temperatures from the 
