Barley Grain in Relation to Localized Water Absorption. 387 
Alcoholic extract of chlorophyll. When sections were placed in a freshly 
prepared solution of chlorophyll in alcohol, the same membranes were 
stained green. The oil of the aleurone cells was also stained. 
Chlor-zinc-iodine. Sections mounted in this reagent gave instructive 
results, as a certain amount of swelling occurred. The three membranes 
were stained a deep yellowthe walls of which these membranes formed 
the superficies became blue. In the sub-epidermal layers of the paleae, the 
blue colouring was pronounced around the cavities of the ceils and shaded 
to the middle lamellae. The perforations in the transverse walls of the 
large cells of the paleae were made very evident. 
Caustic potash (2*9 per cent, for 12 hours) followed by alkanna. The 
course of each of the three membranes was traced in a series of red dots, 
those of the outer epidermis of the tegmen being much larger than the 
others; the oil of the aleurone cells was stained red. The nucellar 
epidermis was made evident. 
Sclmltze's macerating fluid . Sections were gradually heated in this 
fluid on the slide, rinsed in water, and then treated with Scharlach R. The 
three membranes were stained red, droplets occurring in their course. 
Droplets also stood at the cut edges of the membranes. This treatment, 
as also the prolonged treatment with caustic potash, caused the fatty 
matter impregnating the walls to aggregate^ 
Concentrated sulphuric acid. The membranes resisted this reagent and 
remained undissolved ; the aleurone cells became tinged with pink, probably 
indicating the presence of a glucoside. 
By reason of the tests thus applied the three membranes were judged 
to be cuticular, the one delimiting the outer border of the tegmen being of 
considerable thickness. 
(c) Possible alteration of the membrane by penetrating substances . 
An endeavour was made to determine the effect of solutions, more 
particularly those found to penetrate the grain, upon the cuticular mem¬ 
branes. The method of procedure was as follows: selected sections, not 
often complete sections of the grain but only of the convex side with the 
coverings, were placed for varying periods, extending from hours to days, 
into the solutions. When taken out they were rinsed in distilled water and 
mounted in glycerine, with or without previous staining with Scharlach R. 
In this way solutions of ethyl acetate, trichloracetic acid, acetic acid, osmic 
acid, dilute ammonia, sulphuric, nitric, and hydrochloric acids were tried. 
No good evidence was obtained that was pertinent to the question of the 
penetration or non-penetration of these solutions into the grain. The 
cuticular membranes blackened quickly in osmic acid, while after ten days’ 
immersion in ITSOq, HN 0 3 , and HC 1 , of 10 per cent, strength, the 
membrane gave good reactions with Scharlach R. 
