760 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
was the pigment used. In the first series beer-yeast was the organism, 
and in the second and third the typhoid bacillus. The results with 
regard to the yeasts were that they showed, while alive, great resistance 
to the inception of dyes, but when killed, either by heat or by chloro- 
form, they were easily stained. 
The vegetative cells of the bacteria showed, it is true, a certain 
resistance, but the degree of this was very variable ; that is to say, in 
some cases there was little or no difference between the dead and living 
cells, while in other instances it was (e. g. typhoid bacillus) very marked. 
Another inference which the author derives, partly from his own 
experiments and partly from those of Birch-Hirschfeld with phloxin- 
red, is that the death of the vegetative cell is not necessarily associated 
with the inception of pigment, although it would seem, to us at least, 
that it is rather a question of time. 
The experiment was as follows. Typhoid bacilli were incubated 
for 1 hour at 37° in methyl- violet solution 1 : 6000. At the end of this 
time all the bacilli were stained, and when 5 ccm. were cultivated on a 
plate, 63,000 colonies appeared. At the end of 2 hours only 10,450 
colonies came up, and at the end of the third hour none. Of course this 
shows that the pigment becomes more and more noxious, and therefore 
possesses a disinfecting property. 
Blue Milk* — Herr L. Heim finds that the bacillus of blue milk is a 
short mobile rodlet with' rounded ends, and, when stained, shows bright 
spots which do not impart the notion of their being spores. Neither 
endogenous nor free spores were observed in drop-cultivations, nor could 
the club-shaped form of this bacillus be verified by the author, but the 
interesting observation of the two distinct varieties, when cultivated on 
plates, was made. These varieties, though breeding true, behaved alike 
on all other points. 
The most favourable for the pigment-formation was ordinary gelatin, 
to which 0 • 2-0 • 3 per cent, of lactic acid had been added ; but potato was 
also a very suitable medium. 
The tenacity of the bacillus was tested by drying blue milk, as a 
pure cultivation, on silk threads. After having been kept for 226 days, 
the pure cultivations were found to be viable, and the milk threads 
after 114 days. 
To heat the bacilli are very little resistant, being killed in 10 minutes 
at 55°, and in 1 minute at 80°, a fact which argues against spore-formation. 
Between 30° and 40° the bacteria developed no pigment, and their 
growth diminished on all media. 
By the action of disinfecting media it was found that the bacteria 
were destroyed in 3 hours by 3 per cent., in 5 minutes by 10 per cent, 
soda solution, in 30 minutes by 1 : 300 salicylic, while boracic acid had 
no effect. 
Anaerobic pyogenic Bacillus.f — M. Fuchs found in the pleural sac 
of a rabbit, which had died spontaneously, a large quantity of foal- 
* Arbeiten aus d. Kaiserl. Gesundheitsamte, v. pp. 518-36. See Centralbl. 
f. Bakteriol. u. Parasitenk., viii. (1890) pp. 46-7. 
t Inaug. Diss., Greifswald, 1890, 8vo, 30 pp. See Centralbl. f. Bakteriol. u. 
Parasitenk., viii. (1890) pp. 11-12. 
