21(3 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
such as suberin, lignin, paragalactan, &c. ; the middle lamella never 
contains cellulose. 
The crystals always yield dextrose as the result of hydrolysis ; and 
there is therefore only one kind of cellulose. The so-called mannose- 
cellulose obtained from coffee-seeds is a mixture of true cellulose and a 
new carbohydrate with the formula C 12 H 22 O n , which he calls “ para- 
mannan.” Cellulose appears to occur in different physical modifications, 
distinguishable by their solubility in alkalies. Under the term “ hemi- 
celluloses ” Gilson includes all the carbohydrates present in the cell- 
wall which are not coloured blue by chlor-zinc-iodide, such as pectina- 
ceous substances, reserve-cellulose, paragalactan, paramannan, &c. 
Chemistry of the Cell-wall.* — Herr E. Schulze gives a detailed 
account of the chemical differences between true celluloses and hemi- 
celluloses. The latter are distinguished by being readily soluble in hot 
dilute mineral acids, with formation of glucoses. On hydrolysis they 
form galactose, arabinose, xylose, &c., never true dextrose. The author 
finds these substances in the seeds of Leguminosse ( Lujpinus luteus , 
Soja hispida , Pisum sativum , Vida Faba ), and in the bran of wheat 
and rye. They are also soluble in organic acids and in dilute alkalies, 
and are readily oxidized. True cellulose is readily transformed into 
grape-sugar by hydrolysis, mannose being, in some cases, produced in 
addition ; galactose is never produced. It is probably therefore a poly- 
merous anhydride of grape-sugar, or occasionally of mannose. Mannose- 
cellulose presents otherwise all the properties of ordinary cellulose, and 
has the same composition. 
Formation of Folds in Cell-walls.f — Herr L. Kny discusses the so- 
called folds in the cell-walls of the antherids of CJiara , and in the epi- 
dermal cells of the petals and the branched palisade-cells of the leaves 
of certain plants. As the result of measurements at different periods of 
their growth, he concludes that, with the single exception of the palisade- 
cells in the leaves of Pinus austriaca , the folding is only apparent. The 
deepest spots of the folds are the places where there has been the least 
superficial growth, on each side of which the membrane has protruded 
outwards in a sharp curve. In the branched palisade-cells of Pinus 
austriaca , there has been, on the other hand, an active growth of new 
cell-wall. 
Transverse Lamellation of the Membrane of Bast-cells. :£ — Herr C. 
Correns has investigated this structure, chiefly in the case of species of 
Apocynaceae. He finds that the transverse lamellation depends on the 
formation of strongly refractive lamellae, which cross the stratification 
nearly at right angles, sometimes anastomosing, but not forming a true 
network. Either all or only a few of the layers in a cell- wall may 
show this transverse lamellation. In the outer layers the lamellation may 
occur together with striation. The light-coloured transverse lamellae 
are always very thin. They have become ^infiltrated by an unknown 
substance which is not albuminoid. 
* Zeitschr. f. phys. Chemie, xvi. (1892) pp. 387-438. See Bot. Centralbl., lv. 
(1893) p. 157. f Ber. Deutsch. Bot. Gesell., xi. (1893) pp. 377-91 (2 figs.). 
\ Tom. cit., pp. 410-25 (1 pi. and 2 figs.). Cf. this Journal, 1892, p. 56. 
