244 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
ing if this fluid does not come from cells, and turning his opponent’s 
flank by discussing if it really possess bactericidal properties. The 
experiments of Metschnikoff on the immunity of guinea-pigs to Vibrio 
A letschnilcovi are recalled in support of the alexocyte theory. As to 
the objection of making a general theory of immunity from experiments 
in vitro, the author minimizes its force by pointing out that by suitable 
means the granules can be driven from the cells into the plasma, which 
then shows increased bactericidal power, and he concludes by referring 
to the observations of Kanthack and Hardy, who found that the bacteria 
were rendered harmless by the action of alexin granules before they 
were attacked by the phagocytes. 
Ammoniacal Fermentation of Earth.* — MM. A. Muntz and H. 
Condon have made experiments for the purpose of ascertaining whether 
the formation of ammonia is due to chemical or microbic action, or is 
the result of the conjoint action of these forces. Earth from different 
localities (Champagne, Limousin, Joinville) was first sterilized at 120°. 
Equal quantities, 100 grm., of sterilized and non-sterilized earth were 
mixed with like quantities of dried blood, and after 67 days the amount 
of ammonia formed was determined. No ammonia was formed in the 
sterilized mixture, while by the three samples of non-sterilized earth, 
111, 41, and 59 mgrm. of ammonia were formed. 
Further experiments were made in order to ascertain if the production 
of ammonia was due to the action of a special ferment, or was to be 
ascribed to several or indeed any of the microbes inhabiting the soil. 
Seven different micro-organisms were isolated, and experiments made 
from pure cultivations of these in bouillon and in earth mixed with 
inorganic manure. All these organisms produced ammonia ; and as these 
seven species, isolated haphazard, were able to do this, the authors con- 
sider it a legitimate conclusion that the ammoniacal fermentation of 
the soil is, unlike the process of nitrification, a function common to the 
various micro-organisms infesting it. 
Microbes and Fatty Matter. - ] - — Prof. E. Duclaux finds that microbes 
protect fatty matter against the too intense action of the oxygen of the 
air. This protective action would appear to be due to the fact that 
saponification is notably increased under the influence of certain micro- 
organisms, while oxidation predominates under circumstances which pre- 
vent the development of these microbes ; thus, for example, when cheese 
is kept in the cold oxidation prevails and saponification proceeds very 
slowly. Both these destructive processes seem to act on fatty substances 
when exposed to the air simultaneously, though independently one of 
the other, and each process is of a different nature, saponification split- 
ting up the fatty substance into fatty acids and glycerin, while oxida- 
tion acts first of all on the oleic acid, though it eventually attacks the 
whole mass. The author’s researches were undertaken at the instance 
of a large cheese manufacturer who tried to postpone the maturation of 
newly-made cheeses by keeping them at 0°. The result was that the 
cheeses did not ripen, but acquired that soapy tallowy taste which 
fatty substances acquire as the result of oxidation. 
* Comptes Rendus, cxvi. (1893) pp. 395-8. 
t Ann. Inst. Pasteur, vii. (1893) pp. 305-24. 
