ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
425 
suspensions. A lactocrite with a steam turbine which made 8000 revo- 
lutions a minute was used. In the sediment the different constituents 
of the culture were deposited according to their weight, the spores being 
at the bottom and the rodlets at the top. The most suitable emulsion or 
suspension fluid was found to be iodide of soda. When cultures of hay 
bacillus were centrifuged in this fluid with a specific gravity of 1 • 3, a 
sediment was deposited ; but when the specific gravity was 1 * 4 there was 
no deposit. Hence most of the spores had a specific gravitv of between 
1*35 and 1-4. 
Chemical Action of Pathogenic Micro-organisms.* — MM. L. Hu- 
gounenq and M. Doyon have observed the ferment action of pathogenic 
microbes by cultivating in sterilised glucose solutions containing nutrient 
materials placed in contact with excess of calcium carbonate and main- 
tained at 35° for a definite length of time. Staphylococcus aureus produces 
small quantities of alcohol and inactive lactic acid, the gases evolved 
being hydrogen and carbonic acid. Bacillus coli communis produces 
inactive and dextro-lactic acids, ethylic alcohol, and a volatile acid not 
identified. From anaerobic cultures hydrogen and carbonic acid were 
evolved. A similar result was obtained from tetanus; but with Eberth’s 
bacillus the gases were nitrogen and carbonic acid. Under favourable 
conditions Eberth’s bacillus and B. coli com. decompose alkaline nitrates 
in 1J per cent, solutions, setting free nitrogen and the corresponding 
alkali and utilising oxygen. 
Biliverdin added to a nutrient solution containing Staphylococcus 
aureus, septic vibrio, cholera bacillus, Eberth’s bacillus, or B. coli com., 
is decomposed with the formation of a red colouring matter. Bilirubin 
under the same conditions gives similar results. The red colouring 
matter is soluble in water, and its solution is dichroic. Haemoglobin is 
converted into hsematin by these organisms. 
Necessity of Free Oxygen to Essential Anaerobes.! — Trof. W. 
Beijerinck states his belief in the necessity of free oxygen for all known 
living organisms ; and, instead of essential and potential aerobes and 
anaerobes, he would use the terms aerophilous and microaerophilous. 
All bacteria save spirilla, the greater number of potential anaerobes, the 
majority of infusoria, and probably all the cells of animals and of the 
higher plants, are aerophilous. The microraerophilous are some essen- 
tial anaerobes to which belong the Chromatiums, the sulphur bacteria, and 
Spirillum desulfuricans ; probably also the lactic ferments, some species 
of monads, and some infusoria. 
As far as their development is concerned, the greater part of the 
true spirilla and probably also some monads are aerophilous, but are 
microaerophilous for movement. Thus the consumption of oxygen is 
merely one of degree, and free oxygen a necessity to even essential 
anaerobes. In order to explain away the phenomena of essential and 
potential anaerobiosis, the existence of reserve oxygen in the cell itself 
is assumed. 
* Ann. Cliim. Pliys., vii. (1898) pp. 145-56. See Journ. Chem. Soc., 1899, 
Abstr. ii. pp. 376-7. 
f Arch. Neerland. Sci. exact, et nat., ii. (1899) pp. 397-411. 
