ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 795 



cases to oxidize a compound which is oxidized by platinum-black, but also 

 that in the action of the ferment and of platinum-black on the same 

 compound, the products formed in these actions usually differ. 



The author concludes by noting the action of the ferment on mannitol 

 prepared from manna, and on the mannitol formed by the action of sodium 

 amalgam on dextrose. He states that there can be little doubt that the 

 two compounds are identical. 



Cellulose formed by Bacterium xylinum.* — Mr. A. J. Brown has 

 endeavoured to ascertain whether cellulose formed by the ferment from 

 levulose would yield a dextro-rotatory sugar on treatment with sulphuric 

 acid like ordinary cellulose, or whether a levo-rotatory sugar would be 

 formed. In order to ascertain this, a membrane of the ferment was grown 

 in a yeast-water solution of levulose prepared from pure inulin. The 

 author concludes by stating that the cellulose formed from levulose by 

 B. xylinum yields a dextro-rotatory sugar on hydrolysis in a similar 

 manner to ordinary cellulose ; and a way of converting a levo- into a 

 dextro-rotatory sugar is thus shown. 



Anaerobic culture of aerobic Bacteria.! — According to Prof. M. M. 

 Hartog and Mr. A. P. Swan, Bacillus suhtilis will germinate in appropriate 

 nutritive solutions, and form its " Kahmhaut " and spores, when oxygen is 

 excluded from the space not occupied by the liquid, and replaced by carbon 

 dioxide. The lactic organism of Pasteur, usually aerobic, will also develope 

 and grow in suitable solutions during or after alcoholic fermentation in- 

 duced by SoccTiaromyces, after the oxygen must have been used up and 

 replaced by carbon dioxide. 



Chemical reaction for Cholera Bacteria. | — Dr. 0. Bujwid states that 

 the addition of a 5-10 per cent, hydrochloric acid to a bouillon cultivation 

 of comma bacilli produces, in a few minutes, often in a few seconds, a red- 

 violet colour. The colour increases for half an hour, and in a bright light 

 becomes brownish. The staining is more evident if the cultivation be still 

 warm. The reaction does not take place in impure cultivations. With 

 Finkler-Prior's comma bacilli a similar but more brownish stain takes 

 place, but after a longer time. The reaction which may be effected with 

 other mineral acids does not affect many other kinds of bacilli. 



Changes induced in water by the development of Bacteria.§ — Sig. T. 

 Leone has already demonstrated that the number of micro-organisms in a 

 typically pure water, such as the Maugfall, near Munich, although at first 

 small, yet on standing gradually increases to a maximum, and afterwards 

 rapidly decreases. The development of bacteria induces certain chemical 

 changes in the water ; thus the quantity of oxidizable organic matter gra- 

 dually decreases, whilst the proportion of ammonia increases to a maximum, 

 and then decreases owing to its oxidation into nitrites and nitrates ; on this 

 account, the time which elapses between the taking of a sample and its 

 analysis is an important factor. The consequent changes are divisible 

 roughly into two distinct periods : the first, in which the organic matter is 

 decomposed with production of ammonia ; and the second, in which this is 

 subsequently oxidized. It is further shown, on the other hand, that certain 

 micro-organisms seem to act as reducing agents, reconverting the nitrates 



• Joum. Ohem. Soc. Lond., 1887— Trans., p. 643. 



t Rep. Brit. Assoc. Birmingham Meeting, 1886, p. 706. 



X Zeitschr. f. Hygiene, ii. (1837) p. 52. 



§ Gazzelta, xvi. pp. 505-11. See Joum. Chem. Soc. Lond.,, 1887— Abstr., p. 615. 



