O'Brien . — The Proteids of Wheat . 213 
account of the Gramineae is given, and their aleuron-grains 
were still practically unknown. Thus Godfrin (1884), de- 
scribing the albumen of Zea Mays, states that the endosperm - 
cells contain starch only, the epidermis (presumably the 
aleuron-layer) being filled with a granular protoplasm. 
Johanssen 10 (1888) once more emphasised the fact that 
the starchy endosperm, and not the aleuron-layer, is the seat 
of gluten ; a fact which, he tells us, was stated by Payen as 
early as 1846. As for the peripheral cells of the endosperm 
(the aleuron-cells) — they contain tiny grains of an extremely 
slight resistance, nitrogenous in substance, which are em- 
bedded in a soft protoplasmic mass rich in fatty matter : ’ 
a description very different from that of Schenk. Of the 
more intimate structure of the grains no details are given. 
Haberlandt n , however, in 1890, found that the aleuron- 
grains of Gramineae show no essential difference from those 
of other plants. In particular he describes those of Rye ; 
they contain 1-4 globoids in a ground-substance which is 
soluble in water. 
Liidtke 12 in 1890 published a comparative account of 
the aleuron-grains of four groups of plants ; and for the first 
time those of the Gramineae are adequately dealt with. His 
general conclusion is that Gramineae, Leguminosae, Umbel- 
liferae and Euphorbiaceae form an ascending series as regards 
the developement of the aleuron-grains. He finds that in the 
Gramineae aleuron-grains, as known in other plants, have not 
yet been differentiated. Here they usually consist of a homo- 
geneous central mass which should correspond to the globoid, 
and a surrounding membrane ; of which Wheat affords a typical 
case. His observations as to their ready solubility agree with 
those of Johanssen rather than of Schenk. These grains, 
small and without enclosures, are in fact not real aleuron- 
grains, but similar structures, occurring in a ground-substance 
with a fatty oil mixed in its molecules. In what the simi- 
larity consists, or how it may be stated in terms of their 
chemical composition, is not shown. 
Groom 14 in 1893 took up this part of the subject, and 
