EMILY.
You allude, I suppose, to bread, which is made of wheat-flower?
MRS. B.
Yes. The fecula of wheat contains also another vegetable substance which seems peculiar to that seed, or at least has not as yet been obtained from any other. This is gluten, which is of a sticky, ropy, elastic nature; and it is supposed to be owing to the viscous qualities of this substance, that wheat-flour forms a much better paste than any other.
EMILY.
Gluten, by your description, must be very like gum?
MRS. B.
In their sticky nature they certainly have some resemblance; but gluten is essentially different from gum in other points, and especially in its being insoluble in water, whilst gum, you know, is extremely soluble.
The oils contained in vegetables all consist of hydrogen and carbon in various proportions. They are of two kinds, fixed and volatile, both of which we formerly mentioned. Do you remember in what the difference between fixed and volatile oil consists?
EMILY.