205 
O' Brien . — The Proteids of Wheat . 
and may be drawn out into elastic strands giving under the 
microscope the aniline-blue reaction mentioned under gluten. 
When the alcoholic solution is precipitated with water before 
evaporation and water added during the process, the phy- 
sical properties of the albuminate obtained are considerably 
changed. It forms a tough opaque, rather than a clear viscid 
mass ; in fact, it is now almost indistinguishable from gluten 
prepared in the usual way. This form likewise exactly resem- 
bles gluten in its behaviour to alcohol. 
5o°/ o alcohol extracts a similar albuminate, but not so com- 
pletely, since gluten-strands form in the residue. Also, though 
globulin cannot be dissolved out from the residue, it may be 
found as minute spherical particles in suspension on addition 
of water. Besides this globulin, only a trace of proteid is 
obtained by subsequent addition of water ; magnesium sul- 
phate giving only a slight precipitate, and heat causing only 
the faintest milkiness. 
8o°/ o alcohol extracts an albuminate of exactly the same 
nature as that extracted by alcohol 75%. 
90°/ o alcohol extracts it in smaller quantity. 
Absolute alcohol seems to extract a proteid, forming 
a deep yellow solution. A precipitate forms in it on dilution, 
not on heating ; a precipitate is thrown down by nitric acid, 
soluble in excess, and also in dilute potash. 
For quantitative purposes the albuminate was usually ex- 
tracted by means of a simple condensing apparatus, which 
allowed the same alcohol to repeatedly wash a small quantity 
of flour (3-5 grams) placed in a funnel at the mouth of the flask 
in which the alcohol was kept boiling. Alcohol of about 
6o°/ o was used (50 cc. water and 100 cc. methylated spirit), 
and was first allowed to drain through the flour into the flask 
in the cold. From this the condensed vapour passing over 
has at first a strength of over 90°/ o alcohol, but as loss takes 
place the liquid in the flask becomes more watery, and the 
vapour represents a somewhat more dilute alcohol. At the 
end of from 3-5 hours it is found that all the alcohol-soluble 
proteid has been extracted. Fat and colouring-matter are 
Q 2 
