486 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
emptied of tlieir starch, then the woody parenchyme, then the cells of 
the pith. In this state the wood remains stationary till the middle of 
March. About this time starch-grains begin to reappear in the green 
cortex of the branches, then in the phloem, spreading gradually to the 
xylem. The absorption of the starch in winter is, no doubt, due to 
respiratory combustion ; and the winter is, in fact, the period of the 
year when there is the smallest quantity of starch in woody plants. 
The period of the greatest activity in the formation of starch is imme- 
diately after the close of the winter-rest, before the development of the 
buds and the activity of the cambium. After that, even under favourable 
conditions of a clear shy and high temperature, the amount of starch 
decreases, owing to its absorption in the formation of tissues and to 
respiration. In cloudy and rainy weather the decrease is still greater, 
especially in the parenchyme of the upper surface of the leaf. 
Structure of Starch-grains in Maize.* — By boiling pieces of maize- 
grain in chloroform with a few drops of concentrated chromic acid, 
Dr. L. Buscalioni was able to produce a swelling in the starch-grains 
which showed a peculiarity in tlieir structure. Some of the grains pre- 
sented very numerous straight radial strias, which, proceeding from the 
centre towards the periphery, were grouped in two systems crossing one 
another at an acute angle, so as to break up the surface into a number 
of minute regular rhomboid figures. At a later stage of swelling the 
striae were resolved into punctations. 
Spectrum of Chlorophyll.! — Mr. W. N. Hartley gives the result of 
fresh observations on the spectra of blue and yellow chlorophyll. The 
best solvents for leaf-green he finds to be chloroform and alcohol, but 
the former should be distilled off at once, otherwise a change takes 
place in the solution. Leaves of Anacbaris were chiefly used where the 
quantity of foreign substances is comparatively small. In contrast to 
previous statements, Mr. Hartley asserts that yellow chlorophyll has a 
feeble but distinct absorption-band in the red, and a distinct fluorescence. 
It has also an absorption-band in the orange-red, and exhibits a very 
powerful absorption of all rays beyond the b group. 
The leading characteristics of unaltered leaf-green are those of blue 
chlorophyll, viz. an intense absorption in the red, somewhat stronger 
even than in the violet and ultra-violet. 
The author believes that the molecule of chlorophyll, or one of its 
transformation products, is actually capable of reduciDg carbon dioxide ; 
and he supports the view that the first product of this reduction is 
probably formic aldehyde. 
Aspergillin— a Vegetable Hsematin.} — M. G. Linossier gives an 
account of the pigment of the spores of Aspergillus niger , from which 
it seems that there is here a substance completely analogous with the 
haematin of blood. There is a resemblance in physical characters ; both 
contain a distinct quantity of the same metal, iron ; and both are capable 
of forming, under the action of a reducing agent, but not in vacuo or by 
* Nuov. Giorn. Bot. Ital., xxiii. (1891) pp. 45-7. 
t Journ. Chem. Soc., 1891, pp. 106-24. 
X Comptes Rendus, cxii. (1891) pp. 489-91. 
