214 SUMMARY OF CURRENT RESEARCHES RELATING TO 
through these latter is insufficient, or even when it is entirely suppressed. 
The whole of the nodes of a stem or of a branch contain a larger quantity 
of water than the whole of the internodes. Fruit-stalks contain more 
water than ordinary leafy branches. In those portions of a branch in 
which growth has ceased, the maximum tension is in the uppermost node, 
the minimum in the lowest internode. With regard to the distribution 
of water in different parts of the same internode, the results differed in 
different plants. 
Interchange of Carbon Dioxide and Oxygen between Plants and 
the Atmosphere.* — From a fresh series of experiments, made on Lepi- 
dium sativum and Holcus lanatus f M. T. Schlcesing finds that during the 
first six or eight months of growth, the relation between the volume of 
carbon dioxide consumed and that of oxygen given off by assimilation 
is considerably less than unity. 
(4) Chemical Changes (including Respiration and Fermentation). 
Normal Respiration of Plants.f — Herr W. Detmer finds that the 
optimum temperature for respiration is, for seedlings of Lupinus and 
Triticum, and flowers of Syringa and Taraxacum , about 40° C. ; for seed- 
lings of Vicia and shoots of Abies, 35°, and for potato-tubers, 45°. He 
has established also that seedlings of Lvpinus and Triticum will exhale 
carbon dioxide at as low a temperature as —2° C. 
Transformation of Proteids.J — In addition to asparagin, Herr E. 
Schultze finds another nitrogenous substance, arginin, formed at the 
expense of the proteids in the cotyledons of etiolated seedlings of the 
lupin and gourd. Arginin is a strongly basic substance of the com- 
position C 16 H 14 N 4 0 2 , which forms crystallizable salts. 
Decomposition of Albumen in the absence of Free Oxygen.§ — 
Herr W. Detmer concludes, from experiments made on lupin-seedlings, 
that the results obtained by Palladin j| from seedlings of wheat are not 
altogether correct. He finds that, even in an atmosphere of pure hydro- 
gen, a true decomposition of protoplasm, or separation of its physiolo- 
gical elements, takes place, and not simply an oxidation into asparagin. 
Reduction of Nitrates by Plants.^ — M. E. Laurent recapitulates 
the results arrived at by his previous researches on this subject. 
Germinating seeds and tubers, as well as a large number of other vege- 
table tissues, have the power of reducing nitrates to nitrites, and this 
reduction is a function of vegetable life acting in a medium destitute of 
oxygen. 
7 . General. 
Perfumes of Flowers.** — M. E. Mesnard has investigated the loca- 
lity of the formation of the perfume in a number of flowers (jasmine, 
* Comptes Rtndus, cxv. (1892) pp. 881-3, 1017-20. 
f Ber. Deutsch. Bot. Gesell., x. (1892) pp. 535-9. 
% Landwirthsch. Jahrb., xxi. (1892) pp. 105-30. See Bot. Centralbl., 1892, 
Beih., p. 499. § Ber. Deutsch. Bot. Gesell., x. (1892) pp. 442-6. 
|| Cf. this Journal, 1889, p. 783. 
^ ‘ Notes sur la reduction des nitrates par lea plantes,’ Bruxelles, 1891. See Bot. 
Centralbl., 1892, Beih., p. 434. Cf. this Journal, 1891, p. 220. 
** Comptes Rendus, cxv. (1892) pp. 892-5. 
