ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 351 



ruethylcarbinol, CH 3 — CO — CHOH — CH 3 . The author has found this 

 substance produced also by certain other bacteria, e.g. B. subtilis and 

 Tyrothrix tenuis. 



Reduction of Sulphates by Bacteria.* — ■ A. van Delden, working 

 with Microspira desulfuricans, found that it grew best at 25° C. to 30° C. 

 The organic matters usually present in polluted waters are suitable for 

 the reducing organism. Lactates, malates and succinates are the most 

 suitable organic salts, whilst nitrogen is assimilated in the form of 

 asparagin, peptone and ammonium salts. Nitrates hinder the reduction. 

 Sulphate reduction takes place in canal and river water after a little 

 potassium phosphate, sodium lactate and asparagin have been added ; it 

 is suggested that the reduction might be utilised, in conjunction with 

 an iodometric titration, for estimating the amount of sulphate present 

 in water. Cultivations in gelatin containing hydrogen sulphide produced 

 sulphur at the surface to a depth of about 1 • 5 cm. A bacterium was 

 isolated which does not reduce sulphates, but reduces sulphites and thio- 

 sulphates, and, with limited access of oxygen, oxidises the hydrogen 

 sulphide to sulphur. The bacterium resembles Microspira desulfuricans, 

 and differs from Bacterium Jiydrosulphureum pontican in not growing in 

 air. The author experimented also with Microspira cestuarii, cultivating 

 it in various solutions containing magnesium sulphate and suitable 

 nutrient material, and estimating the amount of hydrogen sulphide 

 produced. The effect obtained was similar to that with Microspira 

 desulfuricans. The reduction of sulphates by Microspira desulfuricans 

 and Microspira cestuarii is a process which is possible, under anaerobic 

 conditions, only in a medium which contains, in addition to sulphates, 

 some suitable organic nutrient material. Sulphate reduction, like de- 

 nitrification, can be effected in the absence of free oxygen. 



Microbe Pathogenic to Rats (mus decumanus and mus ratus).f 

 J. Danysz, during an outbreak of spontaneous disease in field mice, 

 isolated a cocco-bacillus pathogenic to rats. Difficulty was experienced 

 in maintaining the virulence of the organism, as by passing the microbe 

 a certain number of times from rat to rat its pathogenicity was much 

 weakened. This difficulty, however, was got over by making experiments 

 on series of twenty or thirty rats at a time, when it was always found 

 that from the bodies of one or two of these animals a sufficiently virulent 

 culture could be obtained, and that the virulence of this culture might 

 be maintained for two or three months. Such cultures have been used 

 successfully in the destruction of rats on farms, warehouses, etc., and 

 even in a large town like Odessa. The cultures were made in bouillon, 

 and crusts of bread were dipped in it as a bait. In the author's opinion 

 there is in these procedures no. risk to human beings or to other 

 animals. 



Bacteriology and Histology of Mud obtained at a depth of 

 10 m. from a Roman Funereal Pit at the Necropolis of Bernard 

 (Vendee)4 — M. Baudouin, who conducted this investigation, regarded 



* Centralbl. Bakt., 2 ,e Abt., xi. (1903) pp. 81-94, 113-9. See also Journ. Chem. 

 Soc, ccccxcv. (1904) ii. pp. 67-8. t Brit. Med. Journ., (1904) i. p. 947-9. 



J Comptes Rendus, cxxxvii. (1904) pp. 1001-3. 



2 B 2 



