626 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
ferrocyanide, the iron may be perceived to have ascended as much as 
from 20 to 50 or even 70 cm. in half an hour. 
Passive Circulation of Nitrogen in Plants.* * * § — According to M. H. 
Devaux, the tissues of aquatic plants are not equally permeable to different 
gases, carbonic acid permeating them much more easily than oxygen. 
The author draws the following conclusions on the circulation of 
nitrogen. If nitrogen is found in the internal atmosphere of plants in 
a larger or smaller proportion than in the external air, the difference is 
due to the gaseous current produced through the openings. The 
difference of pressure between the external and internal nitrogen 
causes constant diffusion, which tends to re-establish equilibrium. 
(4) Chemical Changes (including Respiration and Fermentation). 
Fermentation of Tobacco.! — Herr E. Suchsland has investigated 
the chemical changes which take place in tobacco after it has been 
gathered and packed, and which result in the formation of aromatic and 
other compounds. He finds them to be of the nature of fermentation, 
comparable to the lactic, butyric, and acetic fermentations. The cause of 
this fermentative process is the presence of large numbers of Schizo- 
mycetes, belonging to the bacterium-, and in smaller quantities to the 
micrococcus-forms. They are of two or three different kinds, but 
their special characteristics are not described. 
Nitrification by a Schizomycete4 — Hr. O. Loew suggests that the 
oxidization of ammonia caused by the nitrifying Schizomycete Nitro- 
monas, is partly complete, as expressed by the equation 2NH 3 + 30 2 
= 2N0 2 H + 2H 2 0, partially incomplete, 2NH 3 + 20 2 = 2N0 2 H + H 4 ; 
and that the hydrogen thus set free immediately combines with carbon 
dioxide to form formic aldehyde, according to the equation C0 2 + H 4 
= ch 2 o + h 2 o. 
y. General. 
African Myrmecophilous Plants.§ — Herr K. Schumann describes the 
species of the African genus Cuviera (Rubiaceae) which furnish abodes 
for ants, viz.: — C. physinodes sp. n., angolensis, and longiflora ; also 
Canthium glabriflorum, belonging to the same natural order, and Barteria 
Nigritiana and fistulosa, belonging to the Passifloraceas. Cola mar supium 
sp. n. (Melastomaceae) possesses bladders on the leaves similar to those of 
other myrmecophilous species of the same order ; but it can only be 
placed provisionally in this category, as the author has not been able 
to detect that the bladders are inhabited by ants. 
Atavism of Plants. || — Baron d’Ettingshausen and Prof. Krasan again 
call attention to the phenomena of polymorphism, and especially of hetero- 
phylly in the Cupuliferae, as an example of atavism. A polymorphic 
species, such as frequently occurs in that order, is a collection of forms, 
some of which are successive, others contemporaneous. 
* Journ. de Bot. (Morot), v. (1891) pp. 130-2. 
f Ber. Deutsch. Bot. Gesell., ix. (1891) pp. 79-81. 
i But. Ver. Munchen, April 20, 1891. See Bot. Centralbl., xlvi. (1891) p. 222. 
§ Ber. Deutsch. Bot. Gesell., ix. (1891) pp. 54-72. Cf. this Journal, ante , p. 73. 
|| Arch. Sci. Pkys. et Nat., xxv. (1891) pp. 257- 74. Cf. this Journal, 1890, p. 635. 
