202 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of the nucleoles as opposed to the conception of their definiteness and 
permanence. He adheres also to his previous view of the essential 
improbability of any genetic connection between the nucleoles and the 
centrospheres. The nucleoles are probably of a fluid consistency ; the 
karyokinetic forces appear to exert a direct influence on them. 
Chemical Composition of the Cell-wall.* * * § — Replying to criticisms 
by Herr E. Schultze,f M. E. Gilson adduces additional reasons for his 
previous conclusions on this subject, viz. : — that in vegetable membranes 
there are always found, side by side with cellulose, other carbohydrates — 
the semicelluloses — which are not coloured blue by iodine reagents, and 
which do not crystallise under conditions in which cellulose does 
crystallise. The reserve-celluloses of Reiss are composed of a mixture 
of cellulose which is coloured blue, and of paramannane which is not 
coloured. These results are obtained from a microscopic, in addition 
to a chemical study of vegetable membranes. 
(2) Other Cell-contents (including: Secretions). 
Diastase in Leaves.J — According to Prof. J. R. Green, the diastase 
in foliage-leaves varies in amount during the day, being greatest in the 
early morning, and least after sunset. This variation is due to the 
action of sunlight. Experiments made on the living leaf of a scarlet- 
runner proved the destructive action of light — whether sunlight or the 
electric light — on diastase, the proportion destroyed amounting to from 
10 to 20 per cent. The proteids in the cells of the leaf act as a screen 
from this destructive influence of light. 
Proteids of Wheat.§ — Dr. M. O’Brien has now investigated the 
proteids of the embryo of the wheat-grain, comparing them with those 
contained in the endosperm. She finds them to consist of three 
globulins — mycosin, vitellin, and albumin ; the insoluble gluten of the 
endosperm appears to take the place of the albumin of the embryo. 
Pectase and Laccase in Plants. || — Pursuing their researches on the 
presence of pectase in plants, MM. G. Bertrand and A. Malevre find this 
diastase in a number of cryptogamic plants, and assert also its very wide 
diffusion in green plants, especially in the leaves when growth is rapid. 
The authors describe a convenient mode of preparing it from lucerne or 
trefoil. 
The oxidising ferment laccase is found by MM. E. Bourquelot and 
G. Bertrand to occur in several fungi examined, belonging to the Basidio- 
mycetes, Ascomycetes, and Myxomycetes, in which the phenomenon of 
oxidation is especially energetic. Its distribution varies in different 
fungi, and in some it is present only at a late period of growth. 
Active Principles of Senecio.1T — M. L. Lutz has found in several 
other species of Senecio the two alkaloids, senecionine and senecine, 
already detected, in minute quantities, in S. vulgaris. In all cases they 
* La Cellule, xi. (1895) pp. 19-25. 
f Cf. this Journal, 1894, p. 583. 
X Rep. Brit. Ass. (Ipswich), 1895, p. 856. Cf. this Journal, 1895, p. 73. 
§ Ann. Bot., ix. (1895) pp. 543-8 Cf. this Journal, 1895, p. 544. 
|| Comptes Rendus, cxxi. (1895) pp. 726-8, 783-6. Cf. this Journal, 1895, 
pp. 330, 649. Bull. Soc. Bot. France, xlii. (1895) pp. 486-8, 618-9. 
