ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
215 
(C) sterilized by filtration through porous porcelain. In other series 
Loch Katrine water was used instead of Thames water. Other experi- 
ments were made with potable water highly charged with vegetable 
matter. It was found that typhoid bacilli from ordinary agar-agar and 
gelatin cultures, on being introduced into steam- sterilized potable water 
in such numbers as not to materially alter the composition of the latter, 
undergo no multiplication. This result was uniformly obtained with 
all the waters used. By first submitting the typhoid bacilli to prolonged 
culture in more and more aqueous media, and then introducing them into 
steam-sterilized Thames water, slight but distinct multiplication of these 
bacilli was observed, although the introduced typhoid bacilli did not 
multiply in steam-sterilized potable water ; the bacilli were found to be 
possessed of very considerable longevity (from 13 to 76 days). The 
experiments distinctly show that in these steam-sterilized potable 
waters the summer temperature of 19° is more prejudicial than a winter 
temperature 6 to 8° to the duration of life of the typhoid bacillus. In 
most cases it was found that the duration of life of the typhoid bacillus 
was greater, and often much greater, in the steam-sterilized than in the 
corresponding waters unsterilized. A comparative experiment of great 
interest was made with Thames, Loch Katrine and deep-well water. The 
duration of life was found to be shortest in the Thames water (9 to 13 
days), longest in the deep-well water (33 to 39 days) and intermediate 
in the Loch Katrine water (19 to 33 days). This result has a very great 
practical importance as indicating the greater danger of typhoid bacilli 
gaining access to deep- well than to surface water, and it is pointed out 
that this danger is in actual practice further enhanced by the fact that 
well-water is almost invariably consumed without storage, whilst surface 
waters are often stored for days or weeks, and in some cases for many 
months. The greater bactericidal power of unsterilized than of steam- 
sterilized surface waters does not appear to be due to a competition 
between water bacteria and typhoid bacilli, but rather to the elaboration 
of products of these aquatic bacteria, which are inimical and prejudicial 
to the welfare of the typhoid bacilli. The Bacillus coli communis taken 
from ordinary agar-agar cultures and introduced into steam-sterilized 
Thames water undergoes considerable multiplication, when under pre- 
cisely similar conditions the typhoid bacillus does not multiply. Intro- 
duced into unsterilized water the B. coli communis exists in the living 
state for a much longer period than the typhoid bacillus. 
Action of Light on Bacteria.* — Prof. H. Marshall Ward describes 
further applications of his method of obtaining photographic records of 
the action of the various rays of light on bacteria. He finds that insola- 
tion not only kills large numbers of the bacteria in river-water, but in 
some cases shows its effects in diminishing the liquefying or zymotic 
action of certain forms, and even in altering their mode of growth. 
Microbe of the Tubercles of Leguminosse.j — In reference to the 
question whether the microbes of all tubercle-producing Leguminosie 
* Proc. Cambridge Phil. Soc., viii. (1894) pp. 128-9. Cf. this Journal, 1894, 
p. 241. 
f Landwirthscb. Yersuchsstat., xlv. (1894) p. 1-28. See Bot. Centralbl., 1894, 
Beih., p. 466. Cf. this Journal, 1894, p. 479. 
