ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
129 
Sputum as a Nutrient Medium for Bacteria.* — Dr. W. Steffen 
regards sputum as a natural cultivation medium, especially for pneumo- 
cocci, strepto- and staphylococci, and diphtheria bacilli. The sputa 
most suitable are the clear mucoid and pneumonic expectoration, and 
these may be added to other nutrient substances or prepared alone in 
test-tubes. Any coarse impurities are first removed and the sputum 
sterilised in the usual manner. 
Qualitative Bacteriological Examination of Water. f — Herr van 
der Sleen made comparative researches on three kinds of water (marsh, 
river, and spring). Chemical examinations of the three varieties vvero 
carefully made from time to time. For the bacteriological analysis 
1 ccm. of the marsh and spring water and 0*1 ccm. of the river-water 
were used and the rapidly liquefying colonies on gelatin were killed with 
a drop of glycerin and sublimate. Observations were made on the 
influence of temperature and the alkalinity of the medium. In all 400 
bacteria and 77 species were described and photogiaphed. The value 
of filtration was also tested by passing the impure water through a sand 
filter, and afterwards through an Anderson’s purifier. No better results 
were obtained than by using the sand filter alone ; the KMn0 4 -figure 
was however lowered. 
Besides the 77 species of Bacteria Penicillium glaucum and pink 
yeast were found. No cholera bacilli were detected, though a vibrio 
closely resembling cholera was sometimes present. Among the 
organisms repeatedly observed were Proteus vulgaris and mirabilis ; 
Bacillus coli , subtilis , and ramosus ; many putrefactive bacteria, e. g. 
fluor., liquef., aureus , longus, tenuis , non-liquef ., punctatus, and gaso- 
f or mans. 
Bactericidal Action of Metals.J — Attention is called to a paper by 
Dr. Meade Bolton on the effects of various metals on the growth of 
certain bacteria. This gentleman has tested the bactericidal effect of 
various metals. For the most part agar plates were used, and bits of 
metal were put on as soon as the agar was inoculated with the micro- 
organism. In some cases the metals were absolutely pure; in some 
cases they were commercial but marked chemically pure ; in one set 
brass foil was used, and a few preliminary experiments were made with 
impure metals. A notable result is that it is those metals that are re- 
sistant toward chemical reagents in general which fail to show any 
reaction, or do so only to a limited extent. On the other hand, the 
metals that are readily attacked by chemical reagents all exhibit a 
marked inhibitory action on the growth of the bacteria. The effect is, 
therefore, probably due to a solution of the metal in the medium, and 
putting bits of metal on the cultures is really equivalent to the addition 
of a small amount of that salt of the metal formed by the action of the 
nutrient medium. 
* Inaug. Diss., Berlin, 1894. See Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., 
xviii. (1895) p. 464. 
t Haarlem, 1894. See Centralbl. f. Bakteriol. u. Parasitenk., l t0 Abt., xviii. 
(1895) p. 465. % Amer. Natural., xxix. (1895) pp. 933-6, 
1896 
K 
