350 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Aleurone-grains.* — Herr T. Liidtke discusses these bodies from the 
following points of view: — (1) Behaviour towards reagents; (2) com- 
parative investigation of their morphological characters ; (3) the changes 
induced in them by the swelling of seeds in water ; (4) their develop- 
ment in the ripening of seeds ; (5) their absorption in the germination 
of seeds. In a fully developed aleurone-grain the following parts are 
to be distinguished :—(l) The membrane; ( 2 ) the ground-substance 
(matrix) ; (3) the inclosed substances, consisting of protein-crystalloids, 
globoids, and crystals of calcium oxalate. 
Under the second head the author distinguishes the following four 
types: — (1) Graminese-type ; grains small, without inclosed substances 
or globoids (Graminese, Cyperaceae) ; (2) Leguminosse-type ; larger or 
smaller grains containing globoids (Papilionaceae, Caesalpinieae, Cru- 
ciferae, Banunculaceae, Liliaceae, &c.); (3) Umhelliferse-type ; grains 
larger (5-11 /x), containing globoids or crystals (Umbelliferae, Com- 
positae, &c.) ; (4) Euphorhiacese-type ; grains of the most perfect 
development (Coniferae, Palmae, Euphorbiaceae, Solanaceae, Labiatae, &c.). 
Those aleurone-grains which contain no inclosures except globoids 
resist the action of water better than those which contain crystals. The 
formation of crystalloids and globoids is, according to the author, not a 
physico-chemical process, for all the inclosed substances are formed by 
the vital activity of the cell. The mode of absorption of the aleurone- 
grains on germination differs in different seeds, and is described in 
detail in a number of examples. 
Carotin.'!' — Herr H. Immendorfif finds carotin to be a normal and 
constant product of vegetable life, and to be always present in leaves. 
He gives it the formula C 20 H 3 g. The mode of extracting this substance 
is given in detail, and the author states that it is the only yellow or 
yellow-red constituent of normal chlorophyll. He finds it also in 
etiolated leaves, and in those which have assumed their autumn tint. 
M. Arnaud | gives the percentage of carotin found by analysis in a 
number of plants. It varies with the species and with the period of 
growth, generally increasing up to the time of flowering, and then 
diminishing gradually until the fall of the leaves. According to this 
author, it always accompanies chlorophyll in the leaves; and, like 
chlorophyll, has a tendency to disappear in the dark. 
Solanine.§ — M. E. Wotczal gives the following as the only trust- 
worthy microchemical tests for solanine, viz. (1) Mandalin’s vanadin- 
sulphuric acid, i. e. 1 part of ammonia meta-vanadinate in 1000 parts of 
trihydrate of sulphuric acid; (2) Brandt’s reagent, i. e. 3 grains of 
sodium selenate in a mixture of 8 ccm. of water and 6 ccm. of pure 
sulphuric acid ; and (3) pure sulphuric acid. The first is especially a 
test of extraordinary delicacy; and the series of changes of colour 
which it brings out in a preparation containing solanine is described in 
detail. 
* Ber. Deutsch. Bot. Gesell., vii. (1889) pp. 282-90, and Jabrb. f. Wiss. Bot. 
(Pringsheim), xxi. (1890) pp. 62-127 (3 pis.). 
t Landwirtsch. Jahrb., xviii. (1889) pp. 506-20. See Bot. Centralbl. xli. (1890) 
p. 210. X Comptes Eendus, cix. (1889) pp. 911-4. Of. this Journal, 1887, p. 983. 
§ Arb. Naturf.-Ver. Kasan, xviii. (1888) 103 pp. ; xix. (1889) 74 pp. (Russian). 
See Bot. Centralbl., xli. (1890) p. 100. 
