ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
407 
but within the body of animals sensitive to anthrax ; hence it is possible 
that the protective proteids of the rat may be used as a remedy against 
anthrax. 
Bacillus denitrificans.* — After noticing very shortly the history of 
denitrification, MM. E. Giltay and J. H. Abcrson describe and discuss a 
microphyte which has the power of completely reducing nitrates to 
nitrites. Morphologically it appears to resemble the Bacterium deni- 
trificans a and j3 of Gayon and Dupetit, and the fermentation it pro- 
duces approaches that effected by those microbes — indeed the only 
difference between the action of Bad. denit. a and Bac. denit. seems 
to be that the former produces monoxide of nitrogen as well as 
nitrogen, both decomposing all the nitrate. 
The physiological significance of the fermentation phenomena 
points to indirect aerobiosis — in other words they obtain sufficiency of 
oxygen by splitting up the nitrate and setting free the nitrogen, 
although it is possible that some of the latter is utilized as nutriment. 
An interesting fact observed in the course of cultivation was that 
the presence of carbonate of lime favoured the denitrifying process, the 
crystals being covered with the bacilli. 
The bacillus is a double rodlet 1*5 to 3 p. long and about O' 5 p 
broad, but single individuals are also met with. It was isolated from 
earth and air on plates made from 10 per cent, gelatin and 0’2 per 
cent, infusion of earth ; also by means of ordinary gelatin-bouillon 
and from the air by means of a medium containing nitrates. It was 
also cultivated in the following medium : — 2 grm. nitrate of potash, 
1 of asparagin, 2 of sulphate of magnesia, 5 of citric acid, 2 monophos- 
phate of potash, 0 - 2 calcium chloride, and a couple of drops of 
perchloride of iron to the litre of water. 
This medium was afterwards modified by substituting 2 grm. 
glucose for asparagin. 
The addition of a small quantity of carbonate of lime was found to 
favour the reducing action of the microbe. 
The method pursued by the authors for determining the kind 
and quantity of gas developed by this bacillus is then discussed at 
some length ; a special apparatus for collecting the gas was devised 
and is depicted in an illustration. But the sum and substance of these 
experiments is that when the fermentation was concluded no nitrous or 
nitric acid or ammonia was found in the nutrient medium, the amount 
of nitrogen set free being (within fractional limits) equal to the 
quantity of this element contained in the medium. 
Bacillus cyaneo-fuscus, a pigment-Bacterium.f — M. W. Beyerinck 
describes the life-history of a new pigment-bacterium which he has 
isolated from size and glue and also from “ Edamer ” cheese. The 
former are so vitiated by the action of the bacillus that they become 
black and do not set ; in the cheese the bacillus sets up a disease known 
as the “ blue disease.” Yet these gelatinous and caseous substances 
are not the natural habitat of the micro-organism, its proper dwelling- 
place being earth and water ; indeed, in their foreign abodes these 
* Arch. Neerlandaises Soi. Exaot. et Nat., xxv. (1891) pp. 311-61 (1 pi.) 
t Bot. Ztg., xlix. (1891) Noe. 43-7 (1 pi. and 7 figs.). 
