203 
O' Brien . — The Proteids of Wheat. 
again into solution when water or alcohol is added till the 
previous proportion is approximately restored. Towards 
dilute salt-solution it behaves as towards water, a precipitate 
being formed which disappears on slight addition of alcohol. It 
is precipitated by ether, but the precipitate disappears on 
dilution with water or on evaporation of the ether. These 
are all obviously phenomena due to successive hydration and 
dehydration. 
The solution is slightly acid, and on neutralisation with 
potash a precipitate is formed. This is of a different character 
from the hydration precipitates already mentioned, for it 
redissolves, not on addition of alcohol to the original strength, 
but on further addition of potash. This solution may be 
precipitated by dilute acid : the precipitate thus formed is, 
however, not soluble in dilute acid, but redissolves in 75°/ o 
alcohol. That is, dilute alkali (KOH, *5%) can convert the 
proteid into an alkali-albuminate, whilst dilute acid (HC1, 
\5°/o) cannot transform it to an acid-albumin. May this be 
taken to indicate that it is of itself acid in character, and thus 
incapable of playing the part of a base to other acids ? The 
explanation offered by Chittenden and Osborne 41 of the 
somewhat similar behaviour of zein (from maize) is that a true 
albuminate is not formed ; the proof being in the insolubility 
of the precipitate in excess of acid, whilst it is soluble in 75°/ o 
alcohol. The characteristic tests for zein were applied to the 
alcohol-soluble proteid with the result that exact agreement 
of behaviour was shown. It was examined (i) as precipitated 
by ether, (2) by absolute alcohol, (3) after evaporation to dry- 
ness, with the same results. HC1 (1%), HN0 3 (dilute), do 
not dissolve it ; KOH (i°/ o ) and Na 2 C0 3 (5%) dissolve it, and 
it is precipitated unchanged from the alkaline solution by 
acetic or hydrochloric acid, i.e. the precipitate is soluble as 
before in jf/ 0 alcohol, in dilute alkalis, but not in dilute 
acids. The process may be several times repeated. Strong 
alkali, or prolonged heating with dilute, destroys the solubility 
in alcohol, and renders solution in acids possible. 
This proteid resembles the proteoses in many points. It 
Q 
