ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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be equal to that which gives a well-marked agglutinating reaction in an 
undiluted bouillon culture. 
Growth of the Tubercle Bacillus at a Low Temperature.* * * § — Mr. 
F. J. Reid states that a broth culture of the tubercle bacillus a month 
old was filtered through a sterilised Birkefeld filter. The filtrate 
having been ascertained to be sterile, was then sown with a trace of 
B tuberculosis and incubated at 18°-20°. The bacillus developed well. 
The growth had not the usual flocculent appearance, but was granular. 
Microscopically the organism was unchanged. 
Action of Rennet on Pasteurised Milk.f — M. Ed. de Freudenreich, 
who has made experiments as to the action of rennet, finds that milk 
which has not been heated too long at 68° coagulates perfectly well 
under the action of rennet. Heated longer, or when the temperature 
exceeds 70°, the property of coagulation is in a measure lost. Hence in 
practice it would be possible to pasteurise milk destined for cheese- 
making, provided that after the pasteurisation the bacteria necessary 
for the maturation of the cheese were added. 
Fermentation of Fresh Grass. — Herr O. Emmerling fermented 
freshly cut grass for four weeks, and found at the end of that time that 
the hay produced possessed a somewhat pleasant ethereal odour, and at 
the same time a pungent odour, which was found to be due to quinone. 
Among the organisms isolated were small quantities of moulds, chiefly 
species of Mucor ; and besides hay bacteria, granulobacter, and coccus 
species, Bacillus mijcoides was found. It has been shown that the latter 
organism is capable of fermenting glucose, yielding inactive lactic acid, 
and that it is also capable of hydrolysing cane-sugar, maltose, and gly- 
cogen. No other lactic acid bacterium could be isolated. 
Streptothrix Form of the Swine Erysipelas Bacillus.§ — Prof. Th. 
Kitt records an instance of the bacillus of swine erysipelas assuming the 
streptothrix form when cultivated on a medium composed of blood- 
serum and bouillon. This observation recalls those made on the bacillus 
of tubercle by Coppen Jones and others. The author’s remarks are con- 
firmed by four photographs, three of which exhibit very strikingly the 
streptothrix appearance. 
Bacterium found in Hooping Cough.|| — Drs. E. Czaplewski and 
R. Hensel describe a bacterium which they have detected in the expec- 
toration of numerous cases of hooping cough. The microbe is a bacillus 
with rounded ends. It is extremely small and has some resemblance to 
the bacillus of influenza. It is non-motile and is easily stained, especi- 
ally at the ends. This polar staining suggests the name, Polar bacte- 
rium. The bacilli have no special distribution, are usually scattered 
about irregularly, are mostly free, but occasionally are found within 
cells. The polar bacillus grows on the usual media, but its cultivation 
does not seem particularly easy. The optimum temperature was found 
to be 37° ; and though it grows best with free access of air, the organism 
* Nature, Jan. 6, 1898, p. 221. f Ann. de Micrographie, ix, (1897) pp. 345-60. 
% Ber. Deutsch. Chem. Gesell., xxx. (1897) pp. 1869-70. See Journ. Chem. 
Soc., lxxi. and lxxii. (1897) Chem. Abst., p. 579. 
§ Centralbl. Bakt. u. Par., I 10 Abt., xxii. (1897) pp. 726-32 (1 pi.). 
|| Tom. cit., pp. 641-63, 721-6 (1 pi.). 
