664 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
nibiginosus is a mobile rodlet 1-1 * 5 jx long. It is easily stained with 
the ordinary pigments, but is decolorised by Gram’s method. On 
gelatin the young colonies resemble dewdrops ; but as they grow older a 
brick-red pigment is developed. This only occurs in the presence of 
oxygen, for deep colonies are colourless. The bacillus grows well on 
agar, potato, sterilised milk, and in Uschinsky’s medium, though in the 
last no pigment is formed. B. coccineus is a mobile bacillus, 1*5-2 ^ 
long. It is stainable by Gram’s method. It grows well on the usual 
media. On glycerin-agar (8 per cent.) it forms a crimson-red pigment, 
while on potato the pigment is orange-yellow. 
Both these bacilli possess long flagella, easily demonstrated by 
Loeffler’s method. In old cultures both form long filaments. Besides 
the points already noticed, these bacilli are further distinguished by the 
following criteria. B. rubiginosus has no action on milk, while B. coc- 
cineus coagulates and turns it sour ; in the former the pigment seems to 
be confined to the centre of the colonies, while in the latter it is more 
uniformly distributed. 
Microbiology of nitrification.* — Prof. S. Winogradsky defends his 
position on the theory of nitrification, which would have been turned had 
the observations of Stutzer and Burri on a nitrate-forming bacillus been 
substantiated. The latter stated that their bacillus throve on a gela- 
tinous medium, whereas the author had laid it down as an axiom that the 
nitrite and nitrate-forming bacteria do not flourish on organic media. 
It was also determined by Stutzer and Burri that the oxidation of nitrites 
was a very transient function. The author obtained a sample of the 
material used by Stutzer and Burri (earth from Northeim), and isolated 
therefrom several organisms, among which was the specific nitrate-former. 
The latter, when tested in bouillon, meat-pepton-gelatin, and agar, failed 
to grow, showing not only that the colony was pure, but also its specific 
character. Morphologically and culturally, there was little difference 
between the nitrate-former and three kinds of bacteria, which are de- 
scribed in detail. The views of Stutzer and Burri are therefore erroneous, 
and are to be ascribed to errors of manipulation. ^ 
Inhibitory Action of Air on Nitrate -destroying Bacteria, f — 
Herren A. Stutzer and R. Maul have submitted cultures of Bacterium 
denitrificans i. mixed with B. coli to the influence of constant currents of 
atmospheric air, and found that, in artificial media which are devoid of 
organic nitrogenous compounds, neither B. denitrificans nor B. coli de- 
veloped, though both did so in bouillon. In the course of two days the 
bouillon became turbid, and by the fourth day the nitrate had quite 
disappeared, as shown by the absence of reaction with diphenylamin. 
When a constant stream of air was passed through the medium, the fluid 
became turbid as before, though even on the tenth day a considerable 
quantity of nitrate and some nitrite were present. It would seem, 
therefore, that the copious supply of air inhibits the fermentative action 
of mixtures of B. denitrificans i. and B. coli, just as it does those of 
B. denitrificans ii. and B. coli. 
* Ceniralbl. f. Baldciio 1 . u. Parasiteuk., 2 tc Abt., ii. (1896) pp. 415-28, 449-58 
t Tom. cit., pp. 473-4. 
