ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 501 



Tobacco Bacteria.* — According to Herr C. J. Koning, Diplococcus 

 iabaci and Bacillus tabaci i. play an important part in the fermentation 

 of Dutch tohacco. For examining the flora of fermenting tobacco, 

 surface cultures are recommended. Little bits of leaves are shaken up 

 in physiological salt solution, and the fluid poured over gelatiu plates. 

 B. tabaci i. is a motionless aerobe, and varies much in size in artificial 

 cultures. It does not stain by Gram's method or form spores. At 

 60° it is killed in 20 minutes, at 50° in 5 hours. Peculiar yeast-like 

 appearances were observed in agar cultures some weeks old, but on 

 transference to fresh media the normal growth returned. Asparagin is 

 decomposed with formation of ammonia, nitrate is reduced to nitrite, 

 glucose consumed, and gelatin liquefied. On naturally acid tobacco 

 extract the bacterium does not grow well, and does better when the acidity 

 is diminished. 



D. tabaci forms small round lemon-yellow colonies on gelatin plates. 

 It grows best at room temperature, and, like jB. tabaci i., forms ammonia. 

 It is an essential aerobe, and does well on acid media. Gelatin is 

 slowly and feebly liquefied. Besides the foregoing, other bacteria more 

 or less resembling Proteus were found. These, as well as a potential 

 anaerobe B. tabaci Hi., which appears to have a share in raising the 

 fermentation temperature, are also connected with the fermentation 

 process. 



Tumours of Microbic Origin in Juniperus phoenicea. f — Dr. F. 

 Cavara gives a description of tumours found on the stem and branches 

 of Juniperus phoznicea L. From the internal parts of the tumours were 

 isolated two bacteria, one of which liquefied gelatin rapidly and the other 

 very slowly. The liquefying bacterium was a bacillus with rounded 

 ends occurring in pairs or chains, the joints measuring 2-8 /x in 

 length by 0*7— - 8 /x in breadth. It was stained by Gram's method. 

 The other bacterium was a micrococcus with a diameter of 2-2*5 jx. 

 The elements were arranged in pairs or groups, and occasionally were 

 isolated. In order to test the parasitism of these bacteria, healthy plants 

 were inoculated with cultures of the bacillus and micrococcus. Not 

 being able to obtain specimens of J. phoenicea, the author used J. com- 

 munis. After some months the scar tissue about the inoculation sites was 

 observed to be much thickened, but there was no definite tumour for- 

 mation. There was no difference in the appearances produced by either 

 organism. 



Mechanism of Agglutination. J — Herren Kraus and Seng, pursuing 

 the same line as Nicolle, who showed that inorganic substances like chalk 

 could be agglutinated as well as microbes, have tested other inorganic 

 substances such as Indian-ink, cinnabar, ultramarine, and have found 

 that they can be agglutinated by the addition of alcohol, if they are 

 suspended in a fluid in which a precipitate falls on the addition of al- 

 cohol. From these experiments the authors conclude that the essential 

 features of the mechanism of the agglutinations caused by serum and by 

 chemical substances are precipitates and coagulation processes, whereby 

 the microbes become clumped passively. 



* De indische Mercuur, July 8, 1899. See Centralbl. Bakt. u. Par., 2" Abt, vi. 

 (1900) pp. 344-5. t Bull. Soc. Bot. Ital., 1898, pp. 241-50. 



t Wiener Klin. Wocheuschr , 1899, No. 1. See Beibefte z. Bot. Centralbl., ix. 

 (1900) pp. 218-9. Cf. this Journal, 1898, p. 339. 



