12 
BULLETIN 183, U. S. DEPARTMENT OF AGRICULTURE. 
barley capable of converting certain starches supplied in the place of 
its endosperm. They find that excised embryos are able to grow 
when the scutellum surface is grafted on endosperms in which life 
is extinct. They consider the endosperm no longer a vital tissue 
and claim that the aleurone layer does not secrete enzyms/ assigning 
cytase, as well as diastase, to the scutellum. 
Ling 1 supports Griiss, as opposed to Brown and Morris, regarding 
the extent of the dissolution of cell walls in conversion. TheTatter 
attribute the ''mealiness" of malt to a marked dissolution of the 
cell walls. Griiss holds that the walls become merely transparent. 
Ling finds the walls present hi all parts of the endosperm, although 
affected by cytase. • 
Vines, 2 while working with yeast and agarics, assumes that similar 
enzyms exist in other plants. He finds two classes of enzyms: (1) 
Those that peptonize and (2) those that peptolyse. 
Beaven, 3 while only incidental to the subject of his paper, remarks 
that the starch endosperm of barley is built up in centrifugal order 
and that its outer layer is easily broken down. 
Gibbs 4 states that in the Alsinoidese the greatly reduced endo- 
sperm is active only as an absorptive organ of the food material 
which is here stored in the perisperm. 
Ellrodt 5 finds that small-berried malts give a higher diastatic 
power per gram of original material than do large-berried ones. 
Brown 6 finds that the semipermeable membrane exercises a 
selective action, allowing water to enter the grain, but absolutely 
excluding most substances in aqueous solutions. The absorption 
is uniform in all parts of the grain. 
SOURCE OF DIASTATIC FERMENTS. 
On account of the fact that starch is the form in which most of the 
convertible material is stored, its digestion has received a great 
amount of attention. The process has been ascribed to three sources: 
(1) To a secretion of the endosperm itself; (2) to a secretion by the 
aleurone layer; and (3) to a secretion by the scutellum. 
The theory of the self-digestion of the starch endosperm has been 
conspicuously championed by only two men, namely, Hans teen 7 
1 Ling, A. Presence of cell walls in the endosperm of malts. (Abstract.) Brewers' Journal [New York]^ 
v. 29, no. 10, p. 440, 1905. 
2 Vines, S. H. Proteases of plants. Annals of Botany, v. IS, no. 70, p. 289-317, 1904. 
3 Beaven, E. S. Varieties of barley. Journal, Federated Institute of Brewing, v. 8, no. 5, p. 542-600, 
12 fig., 1902. 
4 Gibbs, L. S. Notes on the development and structure of the seeds in Alsinoidese. Annals of Botany, 
v. 21, no. 81, p. 25-55, 4 fig., pi. 5-6. 1907. Abstract in Botanical Gazette, v. 43, no. 5, p. 349-350, 1907. 
5 Ellrodt, G. Unterschied des Diastasegehaltes von Malzen aus grosskomigen und kleinkornigen Gersten. 
Wochenschrift fur Brauerei, Jahrg. 23, no. 20, p. 243-244, 1906; also in Zeitschrift fiir Spiritusindustrie, 
Jahrg. 29, no. 23, p. 209-210. Abstract in American Brewers' Review, v. 20, no. 7, p. 379, 1906. 
6 Brown, A. J. On the existence of a semipermeable membrane inclosing the seeds of some of the Gram 
inese. Annals of Botany, v. 21, no. 81, p. 79-87, 1907. 
7 Hansteen, Barthold. Ueber die Ursaehen der Entleerung der Reservestoffe aus Samen. Flora, 
Bd. 79, p. 419-429, 1894. 
