1 86 O'Brien . — The Proteids of Wheat. ' 
occurring. On gradually raising the temperature, coagulation 
is found to begin again at from 75-8o°C., and a dense flocculent 
coagulum is obtained : heat, however, of nearly of ioo°C. is 
necessary for complete coagulation. This plainly indicates 
(the absence of albumin having been shown by the complete 
precipitation with MgS 0 4 ) that vitellin is present in addition 
to myosin. This is further shown by the fact that saturated 
salt-solution extracts a globulin from flour ; and perhaps 
by the tendency to form crystals (see later). Where an 
estimate was made, I found myosin -19%, vitellin *819°,/; 
total globulin i-oo9°/ o (cf. total globulin extracted by salt, 
i-oiVJ. 
It may be noticed that oats likewise contain both myosin 
and vitellin (Weyl), as do also mustard-seed and peas (Weyl) 
and maize (Chittenden and Osborne). In fact the distinction 
between the two classes of globulins, though a natural one in 
animal physiology, seems by no means well marked in plants. 
Thus Martin 33 describes a myosin of papaw-juice coagulating 
at 74 0 ; and states that the myosin of wheat may become 
insoluble even at 35°-40°C. Vines suggests the possibility 
of one form of globulin passing over into the other, i. e. of 
plant-vitellin becoming myosin. A third and still more 
soluble form of globulin is described in maize by Chittenden 
and Osborne. Vitellin is, in solubility, a connecting link 
between globulins and albumins ; like the former, it is in- 
soluble in pure water ; like the latter, it is not precipitated by 
saturation with NaCl, but it is precipitated by MgS 0 4 , while 
they are not. These typical degrees of solubility are shown 
by the globulins of wheat (cf. following table, to which albumin 
is added for the sake of comparison) : 
Albumin. 
Vitellin. 
Myosin. 
NaCl (dilute) 
soluble 
soluble 
soluble 
NaCl (saturated) ) 
NaCl (dil. , at 6o°C.) \ 
soluble 
soluble 
insol. 
MgS0 4 (saturated) 
soluble 
insol. 
insol. 
(NH 4 ) 2 S0 4 
insol. 
insol. 
insol. 
globulin of wheat 
is obtainable also 
in a crystalline 
