2i6 O' Brien , — The Proteids of Wheat. 
contrary, stains with iodine, haematoxylin, and aniline-stains, 
and does not dissolve in any of the above-mentioned re- 
agents. Therefore, as compared with an ordinary aleuron- 
grain, the peripheral layer corresponds to the membrane, 
whilst the core unites in itself the characters of globoid and 
proteid ground-substance. 
The degree of the solubility of the core differs considerably 
with the reagent employed, and various characteristic re- 
actions occur. For observation I used sections cut dry, and 
at first treated them with ether to remove oil ; the presence 
of oil, however, does not with most reagents interfere with 
one’s observations after a little experience. My method 
was therefore simply to lay the section of the grain of Wheat 
on a slide under a cover-glass ; to then run in a drop of 
absolute alcohol, in order to get a particular cell or aleuron- 
grain under observation, under the microscope ; and, lastly, 
to irrigate the section with the reagent in question. In some 
cases, where solution for more than a few hours was necessary, 
the sections were kept in the reagent in a watch-glass. On 
running in the more slowly acting reagents the same results 
could be observed by using perfectly dry sections. 
Water . — The core at once appears more distinct, and within 
five or ten minutes seems to be dissolving from the outside ; 
dissolution may also proceed from the centre or may be 
irregular. The process is slow, and may not be completed 
till after one or two days, especially in those cells of the 
aleuron-layer which are still intact. Dissolution is assisted 
by slightly heating the slide. Finally only the peripheral 
part is left, a hollow sphere — this is quite unattacked by 
water even after six days. 
Salt-Solution (NaCl io°/ o ). — At first this acts more ener- 
getically than water, and in free-lying grains dissolution may 
be completed in less than an hour. Solution usually takes 
place in much the same way as in water; sometimes the 
core breaks up into three or four smaller spheres. Ultimately 
the process is less rapid, owing probably to the greater diffi- 
culty with which the solvent penetrates the protoplasmic 
