ZOOLOGY' AND BOTANY, MICROSCOPY, ETC. 609 



to nitrites in 1 per cent, dextrose-broth containing 0*05-0 '23 per cent, 

 potassium nitrate. The extent of the reduction varied with the bacillus, 

 the coli bacillus reducing least and the hay bacillus most nitrate. The 

 strength of the sugar solution was without influence, but the amount of 

 nitrate had a decided effect. An excess of nitrate checked fermentation. 

 Complete disappearance of nitric nitrogen was simultaneous with cessa- 

 tion of fermentation. Denitrification is therefore not due to direct 

 microbic action ; but the products of fermentation reduce nitrates to 

 nitrites and eventually convert them into carbonatos. Any fermentation 

 of sugar, by whatever microbe it is caused, will destroy nitrates when 

 present, and denitrification can only take place in presence of substances 

 which yield denitrifying products of metabolism. 



Fermentation of Cellulose.* — According to M. V. Omeliansky, 

 Bacillus fermentationis cellulosoe attacks cellulose in solutions which 

 contain only mineral salts, the products of fermentation being fatty 

 acids, acetic acid and butyric acid, and the gases carbon dioxide and 

 hydrogen. The fermentation of cellulose described by Hoppe-Seyler 

 is probably effected by some hitherto undescribed organism, and differs 

 from the foregoing in that carbon dioxide and marsh gas are formed, 

 but no solid or liquid products ; it is not the amylo-bacterium. 



Zymase Fermentation."!"— In the process of the fermentation of cane- 

 sugar, Herr E. Buchner states that it is not the whole of the protoplasm, 

 but only a portion of it that acts as a transmitter of the fermenting 

 activity. The idea of "living protoplasm" is not nearly so concrete a 

 one as some writers have maintained. 



y. General. 



Sudden Appearance of New Species.} — M. H. de Vries records the 

 appearance, in a culture of Oenothera Lamarckiana, of a single individual 

 differing in several distinct points of structure from the parent-form, 

 and possessing all the characters of a distinct species, which he names 

 CEnothera gigas sp. n. These specific characters were renewed for three 

 generations without exhibiting any tendency to return to the parent- 

 form. In another communication § the author describes five other new 

 " species," all derived from the same parent, which maintain their con- 

 stancy. 



Structure of Galls. || — In a lengthy article on the structure of galls 

 caused in various plants by different insects, Herr E. Kiister gives the 

 following summary of the most important conclusions. 



Those galls which result from a superficial growth of the part of the 

 plant attacked are always of simple structure ; a great histological 

 differentiation is found onl) in those which are the result of growth in 

 thickness. Among normal kinds of tissue, the epiderm is that which 

 offers the longest resistance to the action of the gall-irritant ; the foci of 

 formation of the gall are the mesophyll, the cortex, and the pith. The 



* Arch. Sci. Biol. St. Petersburg, vii. pp. 411-34. See Journ. Chein. Soc, lxxviii. 

 (1900) p. 493. 



t Ber. Deutsch. Bot. Ges., xvii. 1899 (1900) Gen.-Vers. Heft, pp. 243-4. 

 X Comptes Eeudus, cxxxi. (1900) pp. 124-6. § Op. cit., pp. 561-3. 



Flora, lxxxvii. (1900) pp. 117-93 (21 figs.). 



