194 O' B run. — The Proteids of Wheat. 
at ordinary temperature may be made to produce a similar 
albumose from gluten, but only by prolonged contact, i. e. 
more than three or four days. The insoluble albumose of 
gluten has been regarded as an insoluble derivate of the 
soluble albumose of flour (as extracted by water in the 
washings of gluten). The behaviour of gluten, once prepared, 
towards water on standing and towards boiling water, indicates 
rather a derivation of a soluble albumose from a less soluble 
form of proteid ; and perhaps the proteose of the washings of 
gluten is similarly derived from gluten in its earliest and (as 
will be shown later) its most soluble stage. In this case, the 
connexion between the albumoses would be as follows : as 
much as can be at once formed by cold water is removed 
in the washing, but more is subsequently formed by boiling 
water and removed as mucin, together with the intermediate 
insoluble phytalbumose. 
The solubility of gluten in alcohol leads directly to the 
question of the constitution of gluten ; for, as has been already 
shown, alcohol has been chiefly used in its analysis. The 
products thus obtained have been mentioned in the historical 
sketch, and may here be tabulated : 
/ insol. in alcohol a. Zymom 
Gluten J \ pptd. on cooling alc.-soln. . . b. Myxon 
} sol. in ale., Glian < not pptd. ; insol. in water . . . c. Glutine 
l ( sol. in water ' d . Mucine 
This is by no means to be taken as a statement that gluten 
consists of four different constituents, which may be separated 
in the way indicated by their solubilities. It is simply an 
acknowledgement of the fact that by treating gluten in certain 
ways certain corresponding products may be obtained, for 
each of which it is convenient to have a name. They have 
frequently been considered as distinct substances which exist 
independently in gluten ; but it seems to me that we might 
with equal justice consider cane-sugar to be merely a mixture 
of dextrose and laevulose, because on hydrolysis it yields 
these two bodies. There is, moreover, direct evidence against 
their existence as independent constituents of gluten ; this 
