72 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(luced by some other substances, such as wax, sealing-wax, colophane, 
silk, cotton, wool, linen, caoutchouc, wood, sulphur, &c., when dry ; and 
by vigorous roots of other plants. On one another the sporangiferous 
filaments of Phycomyces exercise a slight influence of repulsion. 
(4) Chemical Changes (including Respiration and Fermentation). 
Development of Wheat and Formation of Starch in the Grain.*— 
M. Hebert has studied the development of the wheat-plant in the light 
of recent knowledge obtained as to the composition of straw. Certain 
tables are given which throw some light on the source of the starch in 
the grain. The straw gum, really contained in the stems instead of the 
starch or amylaceous substance formerly supposed to accumulate there 
ready for transportation to the grain, does not appear to be its source. 
It increases in the straw regularly up to the end of maturation, forming 
25-35 per cent, of ripe straw, is insoluble in water, is attacked by acids 
with difficulty, and requires a long time for transformation into xylose. 
It is certain that starch is not formed early in the lifo of tho plant and 
then transported, and it is equally certain that it is not formed by 
chlorophyll action during maturation, for at that period the leaves are 
yellow and withered. As to nitrogenous matters, there is an accumulation 
in the straw and subsequent migration into the grain. 
Action of Diastase upon Starch.f — Herr A. Meyer contests Krabbe’s 
statement that the diastase-ferment does not penetrate between the 
micellm in channelled starch-grains, and thus cause their dissolution. 
He finds in many, if not in all cases, the surface of the starch-grains to 
show splits and crevices before the commencement of their dissolution. 
New Fermentation of Starch.J — Sigg. A. Sclavo and B. Gosio state 
that starch paste which had been kept for four months and had decom- 
posed, acquired an agreeable odour due to the presence of alkyl buty- 
rates, and subsequently an odour of valeric acid was perceptible. This 
starch paste was found to have the power of inducing the same change 
in other starch paste. The cause of this change is a bacillus ( Bacillus 
suaveolcns ) which was isolated. The bacillus has no pathogenic pro- 
perties, will develope on all the usual nutritive solutions, and presents a 
characteristic appearance in plate cultures ; it does not liquefy gelatin. 
In order to develope spores, the bacillus requires air and a temperature 
of 22-29°, and a nutritive substance as neutral as possible. It converts 
starch gradually into dextrin and glucose, with formation of alcohol, 
aldehyde, formic, acetic, and butyric acids, together with ethereal 
substances of an agreeable odour. 
Alcoholic Fermentation with Saccharomyces apiculatus.§— Herr C. 
Amthor found, from experiments made by fermenting beer-wort with 
Saccharomyces apiculatus, that the maximum volume of alcohol, viz. 1 • 49 
per cent., was reached in about two years, and hence that it was of no 
practical value for estimating dextroso. 
* Ann. Agronom., xvii. pp. 97-115. See Journ. Cliem. Soc., 1891, Abstracts, 
p. 1285. 
f Ber. Deutscli. Bot. Gesell., ix. (1891) pp. 238-43. Cf. this Journal, 1890, p. 749. 
j Arch. Ital. Biol., xiv. See Journ. Chem. Soc., 1891, Abstracts, p. 1284. 
S Clieiniker Ztg., 1891, p. G70. See Centralbl. f. Bakteriol. u. Parasitenk., x. 
(1891) pp. 157-8. 
