456 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Bacteria of Hot Springs.* — Herr Karlinski found two species of 
bacteria in two hot springs in Bosnia, the temperature of one being 51°, 
and of the other 58°. Both bacteria developed well at from 50°-60°, but 
did not grow at room temperature, while at 80° their growth stopped. 
On potato the first species formed pale yellow, moist, round colonies, 
consisting of short, thick rodlets, devoid of movement, and not forming 
spores. The bacterium grew on all the ordinary media ; in the presence 
of oxygen it formed acid, and was not pathogenic. The second species, 
Bacillus Ilidgensis capsulatus, is a fairly long thin rodlet, possessing a 
distinct capsule. On potato it forms circular, flat, snow-white, porcelain- 
like colonies, and grows well on all the ordinary media. At a tem- 
perature of 68° spore-formation was observed. 
Bacteria from the Air of Hew York.j — Mr. IT. G. Dyarhas made an 
attempt to determine the identity of the bacteria commonly occurring 
in the air of Hew York. Twenty-four Micrococci and forty-four Bacilli 
w’ere found in the air of the city, but no Spirilla. The cultures were 
obtained by exposing gelatin plates for from one to five minutes in 
various situations. The yeasts, Cladotlirices , and moulds, were disre- 
garded. The systematic description of the species isolated and of others 
used for purposes of identification and comparison is preceded by 
remarks on species among the Bacteria, the identification of old descrip- 
tions, and variation in Bacteria. Under the last head experiments were 
conducted with B. lactis enjthrogenes to test the range of variation in a 
given species, and the question is considered under the heads of Slight 
Continuous Variations, Sports or Discontinuous Variations, and the 
Effect of Environment. The author infers from his experiments as to 
variability that “ it is premature to assume that races of bacteria are 
produced by the direct action of the environment.” Bather the species 
possess, first, a power of continuous variation, producing intergrading 
varieties, which power is, under a long process of natural selection, capable 
of adapting them to various situations or functions ; second, a power of 
considerable discontinuous variation, producing “ sports,” dimorphic or 
polymorphic forms or races (which may revert to type spontaneously, 
and which are distinguishable from true species only by the occurrence of 
such reversion), and ultimately species by the lapsing of the capability 
of reversion. 
Special Action of Serum of Highly Immunised Animals.J — Mr. H. 
E. Durham has investigated some of the effects produced on microbes in 
vitro by the serums of highly immunised animals. The bacteria used 
were the cholera and other vibrios, typhoid bacillus, Bacillus coli com- 
munis, and B. pyocyaneus. It was found that when to an emulsion of 
actively motile microbes minute quantities of potent kinds of serum were 
added, the most prominent effect was the aggregation of the bacteria into 
“ clumps ” ; this was associated with loss of motility and inhibition of 
growth. The reaction is said to be “ complete ” when all the clumps 
settle down, leaving a perfectly clear fluid. AYith regard to diagnostic 
* Hyg. Kimdscliau, 1895, No. 15. See Centralbl. f. Bakteriol. u. Parasitenk... 
l te Abt., xix. (1896) p. 471. 
f Ann. New York Acad. Sci., viii. (1895) pp. 322-80 (2 figs.). 
% Proe. Boy. Soc., lix. (1896) pp. 224-6. 
