ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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Amentiferae. He states, moreover,* that in both the dry and moist 
gangrene of the potato — both known under the name of pourriture — one 
of the main elements is the same parasite. 
Protophyta. 
a. Schizophyceae. 
Biology of Nostoc.f — M. R. Bouilhac states the following as the 
conditions of growth of Nostoc punctiforme in a solution containing 
mineral salts and microbes which have the power of fixing nitrogen. 
Growth will proceed in sufficient light ; but when the light is insufficient 
growth ceases, unless glucose or some other organic substance is present 
in the solution. Green colouring matter is produced under the influence 
of strong light, which does not become yellow in the dark, like the 
chlorophyll of higher plants. 
Nostoc punctiforme.J — In addition to the two ordinary modes of 
propagation of the heterocyst Nostocaceae, by cysts and by hormogones, 
M. L. Sauvageau finds, in Nostoc punctiforme , a third mode, viz. by 
isolated cells distinct from the cysts, which the author terms cocci , 
forming a brown pellicle on the surface of the water. The cocci vary 
in their longer diameter from 3 to 7 p; they multiply by dividing into 
two equal halves, and these again divide into two, thus forming a colony 
of four cells enclosed in a common membrane ; or the division may 
continue until as many as twenty cells are enclosed in a common jelly. 
B. Schizomycetes. 
Central Body of the Bacteriacese.§ — MM. J. Kunstler and P. Bus- 
quet are of opinion that the central body of bacteria which has an areolar 
or reticulate structure, and is enveloped in a special membrane, is not to 
be regarded as a morphological entity. It merely represents the sub- 
tegumentary mass of the body, having chromophilous properties more 
marked than those of the tegumentary layer. It is in this central body 
that those red granules are found which the authors had discussed in a 
previous communication. By some, these red granules were supposed to 
be of a nuclear nature, a view which would lend support to the notion 
that the central body should be regarded as a nucleus. The authors, 
however, give reasons for their belief that the characteristics of the red 
grains were purely physical phenomena. 
Ferment of Cellulose. |] — M. Y. Omelianski, who, some two years 
ago, isolated a ferment of pure cellulose, now gives further characters of 
this microbe. When young it is a straight very thin rodlet (0 • 3-0 * 5 p 
by 4-8 p) ; it elongates with age (10-15 p), and then acquires a uni- 
polar swelling, which eventually becomes a spore, 1*5 p in diameter. 
These spores will stand heating up to 90°, but are killed at once at 
100°. The bacillus is never blued by iodine. It grows not at all or 
badly on the ordinary media. The author used paper, cotton, or an 
amorphous precipitate of cellulose immersed in a mineral solution and 
protected from the action of air. The mineral solution contained 
* Comptes Rendus, cxxv. (1897) pp. 1118-20. f Tom. cit., pp. 880-2. 
X Ann. Sci. Nat. (Bot.), iii. (1897) pp. 367-78 (1 pi.). 
§ Comptes Rendus, cxxv. (1897) pp. 1112-5. || Tom. cit., pp. 970-3. 
