224 O'Brien . — The Proteids of Wheat. 
consider, namely, that the constituents of gluten (gliadin and 
glutenin) exist in flour in the same proportions as in gluten ; 
and that, therefore, gluten may be said to exist as such in 
flour. I find, on the contrary, that these substances may be 
extracted from gluten in varying proportions, according to the 
method employed ; this suggests that the one may be derived 
from the other ; and it is probably the less soluble substance 
(zymom) that is derived from the more soluble (glian) : hence 
the alcohol-soluble substance (glian) is ultimately co-extensive 
with gluten. I was, in fact, able to extract about 8°/ o of this 
substance from flour ; but whilst I must admit that the method 
of extraction was likely to bring with the albuminate or glian 
a certain proportion of other substances, it seems to be highly 
improbable that the quantity of these impurities could be 
such as to reduce the amount of pure glian to the 4 °/ o indicated 
by Osborne and Voorhees. Although in most cases the larger 
quantities of flour with which they worked would enhance the 
value of their results as compared with mine obtained from 
small quantities, yet in this particular instance the repeated 
washing of the smaller quantity of flour may have been more 
thorough than could be possible with a larger quantity. 
The facts seem to me to indicate the existence of one mother- 
substance in flour, which readily undergoes hydration, giving 
rise to gluten. For we can, as it were, intercept the hydration 
at any point, and obtain, consequently, a larger or a smaller 
amount of alcohol-soluble substance (glian), by extracting 
gluten with alcohol at an earlier or later stage in its progress 
to almost complete insolubility. Moreover, it seems almost 
impossible to completely extract from flour the whole of the 
alcohol-soluble proteid with 75°/ o alcohol in the cold; this 
again is suggestive of a gradual hydration of a mother- 
substance. 
