220 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
buds also important changes take place in the amount of starch 
stored up in them in the winter. In most dicotyledonous and mono- 
cotyledonous trees, especially those with hard wood, the reserve-starch 
remains unchanged in the wood and pith from the autumn till May ; 
while in conifers and soft-wood ed trees, such as the lime and birch, 
either the whole or the greater part of the starch is transformed into a 
fatty oil, or a portion of it in the bark into glucose. The carbohydrates 
formed in the leaves descend only through the cortex. 
Physiological Researches on the Floral Envelopes.* * * § — M. G. Curtel 
states that he has noticed that the flower, and the corolla in particular, 
carries on in darkness, or in a feeble light, a more active transpiration 
than does the leaf. This the author proves by experiments with Cobsea 
scandens. The intensity of the respiration is in like manner greater than 
that of the leaf, the quautity of oxygen absorbed being considerably in 
excess of the carbon dioxide given off. A great number of flowers 
contain chlorophyll in their perianth ; sometimes the process of assimila- 
tion may be noted by the disengagement of oxygen, but more often the 
assimilatory process is masked by the respiration. It will be seen then 
that the general result is an energetic oxidization of the floral perianth, 
one of the consequences of this being that coloured substances are formed 
from the chlorophyll, which give to the floral envelopes their character- 
istic brilliancy. 
Formation of Calcium Oxalate.f — Dr. F. G. Kohl supports the view 
of Palladin ^ that oxalic acid must be regarded as a secondary product 
in the synthesis of albumen from amides and carbohydrates. Although 
it has not yet been detected in all cases, it is probable that all Algae and 
Fungi, as well as Flowering Plants, produce oxalic acid or an organic 
acid that can physiologically replace it. Since the cells of fungi absorb 
very little, if any, lime, they cannot, of course yield crystals of calcium 
oxalate. 
The production of oxalic acid by Saccharomyces Hansenii , already 
recorded by Zopf, may be regarded as an oxalic fermentation comparable 
to the acetic fermentation in being a process of oxidation. Dr. Kohl 
distinguishes two kinds of fermentation (1) oxidizing fermentation 
which results in the formation of acetic acid in the Schizomycetes, of 
oxalic and carbonic acid in Fungi, Algae, Muscineae, Vascular Crypto- 
gams, and Phanerogams, and of tartaric and malic acids in the higher 
plants ; and (2) reducing fermentation, resulting in the production of 
alcohol by Schizomycetes and Fungi, and of lactic and butyric acids by 
Schizomycetes. 
Reduction of Nitrates to Nitrites by Plants.§ — M. E. Laurent 
states that many other organs of growing plants have the same property 
as that already known in the case of germinating seeds, of reducing 
nitrates to nitrites. This was determined in the case of tubers, roots, 
petioles, stems, peduncles, and young fruits. The purpose of this 
function appears to be to furnish the living cells with oxygen for the 
* Comptes Rendus, cxi. (1890) pp. 539-41. 
t Bot. Centralbl xliv. (1890) pp. 337-44 (3 figs.). Cf. this Journal, 1890, p. 47G. 
j Cf. this Journal, 1888, p. 247. 
§ Bull. Acad. R. Sci. Belgique, xix. (1890) pp. 478-85. 
