224 Green.— On the germination of the tuber of 
from its watery solution on cooling, so that the latter can be 
diluted to any desired degree. It is precipitated on adding 
alcohol in sufficient quantity to the solution. 
Its relation to sugar is very much the same as that of starch, 
for it is readily converted into sugar by boiling with acids, or 
by heating its watery solution under pressure 1 , the change 
being probably one of hydration, just as is the case with 
starch. Its formula, according to Watts’ Dictionary of Che- 
mistry, is C 12 H 20 O 10 2H 2 0. It differs from starch in not oc- 
curring in the form of grains of definite shape, but being 
crystalline when isolated, and occurring in solution in the sap 
of the cells which contain it. Further, it differs from starch in 
resisting to a very large extent the action of saliva 2 , and in 
being capable of dialysing through a moist membrane. This 
power however is very feeble. Like starch, it has an action on 
polarised light. 
In the plants spoken of, inulin does not replace starch 
altogether, for the latter is found in the sub-aerial parts, but 
it is the only form of carbohydrate reserve-material. 
The chemical changes in the reserve-materials accompanying 
germination have in many cases been shown to be due to 
the action of different unorganised ferments. There is no 
doubt that starch is changed into sugar by a body of this 
description, to which the name of diastase has been given, and 
which has been shown by different writers to occur in almost 
every growing part of green plants. The changes brought 
about in the different proteid reserve-materials have by several 
observers been shown to be due to a similar cause 3 , and cel- 
lulose is demonstrated to give rise to sugar by the same 
agency 4 . Frantl 5 and others have shown that sugar is formed 
from inulin, and in investigating the peculiarities of this change 
the first question that suggests itself is, — Is the conversion due, 
1 Poulsen, Bot. Microchem. p. 88. 2 Cf. infra. 
3 V. Gorup-Besanez, in Ber. Deutsch. Chem. Gesell. 1874, p. 1478. Green, in 
Phil. Trans, vol. 178 (1887) B, p. 39. 4 Green, op. cit. 
5 Prantl, Das Inulin, 1870. — Sachs, Lectures on the Physiology of Plants, Engl. 
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