644 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Similar varieties with partial or complete loss of their chromo- 
genic function, could be obtained by passage through the animal body. 
The conclusion, which is obvious, arrived at by the author from his 
experiments, is that the results of a species of microbe depend on the 
nutrient medium, and if the medium remain the same, on the races 
which that species is in condition of forming. 
New Micrococcus of Bitter Milk.* — Mr. H. W. Conn describes a 
coccus which he has isolated from bitter milk. Its most prominent 
characteristics are the following. Grown on gelatin, it betrays little or 
no tendency to chain formation, although on agar chains consisting of 
four or more individuals are quite common. The organism is of pretty 
fair size, non-mobile, aerobic, and liquefies gelatin with the formation of 
gas. It grows well on agar, potato, bouillon, and in milk. The latter 
medium is rendered bitter, and at a temperature of 35° C. is coagulated. 
The coagulation is probably due to a soluble enzyme, but the author 
failed to isolate the ferment. 
The most remarkable effect of this micro-organism is the viscidity 
and ropiness it induces in gelatin and bouillon when cultivated therein. 
Strings 3 m. long and not thicker than a silk thread may be drawn 
out from these culture media, but it is noteworthy that this phenomenon 
is not observed when the coccus is cultivated in milk. 
From the organism described by Weismann, which is also causative 
of bitter milk, the author’s coccus differs in the fact that it produces 
butyric acid. 
Germicidal Properties of Milk.f — Herr A. P. Fokker finds that if 
fresh goat’s milk be placed in sterilized vessels and then boiled for some 
minutes it coagulates in 24 hours after having been inoculated with a 
minute quantity of B. acidi lactici , but if unboiled it does not do so for 
two to four days. By investigations with plate cultivations and counting 
the colonies, it was shown that, as with blood, there is at first a diminution 
(even to abolition) and afterwards an increase of the fungi. When heated 
for only a short time, the germicidal faculty was not always destroyed. 
M. Ed. de Freudenreich,| in describing his experiments on milk, 
draws attention to the difficulty there is in obtaining it in perfectly sterile 
condition. Only sometimes, even after taking the greatest precautions, 
were the tubes perfectly free from germs. The most simple way is after 
having carefully cleansed the udder, to milk straight away into sterilized 
test-tubes, and this was the method most frequently adopted. But 
another procedure, and one which from a priori considerations ought to 
have yielded better results, was also tried. This was by means of a 
system of glass and caoutchouc tubes so arranged as to connect the 
sterilized udder with the receiving flask in such a way that there should 
be no contamination from the air. Some few quite sterile tubes of 
milk were thus procured, but on the whole we gather that the simpler 
method was not only less cumbersome but more successful. 
The micro-organisms employed in the experiments were the cholera 
bacillus, the typhoid bacillus, the Bacillus Schafferi, and an oval micro- 
* Centralbl. f. Bakteriol. u. Parasitenk., ix. (1891) pp. G53-5. 
t Op. cit., vii. (1890) p. 648. 
j Annales de Microgr., iii. (1891) pp. 415-33. 
