ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
117 
author cultivated liis organisms in hay decoction, and those examined 
were B. Pasteurianum Hausen, B. Kutzingianum Hansen, B. aceti Brown, 
and B. aceti Hansen. The conclusion the author arrived at was that 
the oxidation power of acetic acid bacteria with regard to the monatomic 
primary alcohols diminishes with an increasing quantity of carbon, and 
that B. Pasteurianum , as far as the polyatomic alcohols and glucose are 
concerned, has, with the species tested, the weakest fermentative power. 
Relation of Insects and Rats to the Spread of Plague.* * * § — Mr. 
E. H. Hankin cites some instances of plague which show that there is 
no necessary connection between infection of animals and outbreaks of 
the disease among human beings. From a long series of researches on 
the relation of ants to plague, he has found that these creatures neither 
die of the disease, nor retain the infection for any time. Moreover, the 
infection of ants from plague rats is variable ; for in some localities 
where plague was prevalent, ants were found to be infected, but in others 
not. While several cases of plague were known to have been due to 
direct infection from rats, other epidemics occurred without a single rat 
being affected. On the other hand, an outbreak of plague may occur 
among rats that does not affect human beings. 
Purification of Sewage by Bacteria.f — Dr. Rideal describes several 
methods at present in use for disposing of sewage, the most satisfactory 
being that known as the Exeter system ; and one of the chief objects of 
the author is to show the importance of the preliminary disintegration 
of organic matter before the final oxidation of the elements. This pre- 
liminary disintegration is apparently mainly effected through the agency 
of anaerobic bacteria such as B. prodigiosus and B. fluorescens liquefa - 
ciens, and others, and is not merely a process of oxidation requiring 
only air or oxidising chemicals to bring about the purification. The im- 
portance of bacteria is further seen in the nitrification and denitrification 
which go on during the destruction of putrescible organic matter, and it 
is the knowledge of how these organisms act which has made the recent 
systems of sewage purification on biological lines possible. The general 
principle of self-purification through the^aid of micro-organisms was first 
enunciated by Dupre in 1887, and has been worked out both in the 
United States and in England. 
Diagnosis of Typhoid-like Bacilli in Suspected Water.J — Dr. J. 
Kister records the occurrence of a typhoid-like bacillus in well water 
suspected of harbouring the Bacillus typhosus. The morphological and 
cultural characters were scarcely distinguishable from those of the true 
typhoid bacillus, though colonies on potato showed slight, but not con- 
stant differences. The deciding test was the serum-reaction. This was 
negative, both macroscopically and microscopically : — a good example 
of the value of the serum reaction. 
Capsule of Anthrax Bacillus.§ — By staining with anilin water — 
fuchsin or gentian violet — with phenol-fuchsin, or with Loeffier’s methy- 
len-blue solution, Herr F. Kern has been able to demonstrate the 
* Centralbl. Bakt. u. Par., l te Abt., xxii. (1897) pp. 437-8. 
f Journ. Soc. Arts, xlvi. (1897) pp. 81-93, 115-6. 
X Centralbl. Bakt. u. Par., l te Abt., xxii. (1897) pp. 497-500. 
§ Tom. cit., pp. 166-9. 
