ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 455 



chloride, in which bacterial growth takes place, contains 25 p.c. of the 

 salt. Potassium salts have less effect, growth being very active in broth 

 saturated with potassium nitrate. 



Production of Acetylmethylcarbinol by the Bacteria of the 

 Group Bacillus mesentericus.* — Henri Desmots finds that Bacillus 

 mesentericus vulgatus, B. fuscus, B. flavus, B. niger and B. ruber 

 attack solutions of glycerol, mannitol, dextrose, sucrose, dextrin, inulin 

 and starch. Acetic acid, valeric acid, and small quantities of ethyl- 

 alcohol were produced in each case. By distilling the product a lasvo- 

 rotatory solution was obtained, which reduces Fehling's solution at the 

 ordinary temperature, and with excess of phenyl-hydrazin acetate gives 

 a precipitate of osazone of acetylmethylcarbinol. This osazone forms 

 pale yellow, fern-like crystals, melting at 24:3° C. 



Growth of Bacteria under Altered Pressure. f — G. Marpmann 

 has investigated the influence of alteration in pressure on the growth 

 of bacteria. His method is to introduce into a chamber of glass, or 

 metal, culture masses inoculated on nutrient gelatin, or in fluid media. 

 This chamber contains a thermometer, and is furnished with a screw-top 

 by means of which it is closed hermetically. It is then connected 

 with a manometer. The manometer readings must always be taken at 

 the same temperature. The author found that, from the pressure point 

 of view, bacteria fall into three groups : the gas-producing, the non-gas- 

 producing, and the gas-absorbing. The following were found to pro- 

 duce gas copiously in glucose agar : Bacterium coli, Bacillus pneumonia, 

 B. vulgare {Proteus), B. chauvcei, B. tetani, and B. cedematis maligni. 



Chemistry of Tubercle Bacillus.! — W. Bullock and J. J. R. 

 Macleod find that on extraction with ether dried tubercle bacilli yield 

 large percentages of fatty substances. On filtering the boiled extracts, 

 a white precipitate deposits on cooling. After saponification of the 

 filtrate with sodium hydroxide, two extracts, aqueous and ethereal, are 

 obtainable ; the latter contains some fats ; the fatty acids are probably 

 oleic, isocetic, and myristic. The aqueous extract contains a soap, the 

 fatty acid of which corresponds in melting-point with lauric acid. The 

 filtrates also contain lipochromes. The white precipitate mentioned 

 above can be saponified with difficulty by means of alcoholic potash : 

 a white powder, which is an alcohol, is deposited, and the filtrate 

 contains fatty acids. 



Bacterial Flora of the Male Urethral — H. Pfeiffer has studied 

 the bacterial contents of twenty-four normal male urethras, and found 

 one only culturally sterile. For the study of the posterior portion of 

 the urethra he employed an endoscope tube, and for that of the an- 

 terior portion a medium-sized ear-speculum. Samples of the urethral 

 secretion were obtained from both these situations by means of a looped 

 platinum needle inserted through the tube, or speculum, and rubbed 



* Comptes Eendus, cxxxviii. (1904) pp. 5S1-3. See also Journ. Chem. Soc, 

 ccccxcviii., pp. 276-7. 



t Zeitschr. ang. Mikrosk.,is. (1903) pp. 293-7. 



X Journ. Hvgiene, iv. (1904) pp. 1-10. See also Journ. Chem. Soc, ccccxcviii. 

 p. 277. § Archiv. Derm. u. Syph., 1904, pp. 379-410. 



