ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 99 



together, and occasionally forming threads. Those in the central station- 

 ary part of the colony are only abont a quarter as long, and resemble oval 

 uocci ; they exist usually in pairs. The organism probably does not 

 form spores, since it is killed after 15 minutes' heating at G0° C. It 

 stains with the ordinary aniline dyes, but not by Gram's method. 

 B. Helixoides is actively motile ; but the bacilli in the water of con- 

 densation in an agar culture and in milk are non-motile, very adhering, 

 and form threads ; if these are transferred to salt solution, they at once 

 exhibit active movement. They possess 8-10 flagella. This bacillus is 

 a facultative aerobe. It grows best at about 30° C. Agar stab cultures 

 produce no gas. Gelatin is not liquefied. The colonies are distinguished 

 according to their movement as snail-like, tendril-forming, and cloud- 

 like colonies Detailed account is given of the cultural characteristics 

 on various media ; growth being especially bad in broth, pepton-water, 

 and milk. Indol reation was not observed. It is not pathogenic for 

 mice, rats, rabbits, guinea-pigs, dogs, or pigeons. 



Nutrition of Bacterium Acacise.* — R. Greig Smith, who has already 

 shown that when Bad. acacia, and Bad. metarabinum are sown on 

 saccharose-potato-tannin-agar, luxuriant slimes are produced, from which 

 arabin and metarabin can be obtained, now records observations on the 

 nutrition of Bad. acacm. This organism can produce gum readily in the 

 presence of suitable nutrients ; the best sources of carbon being levulose 

 and saccharose. When subcultivated on sugar-free media, the power of 

 forming gum is temporarily lost. Amides are the best nitrogenous 

 nutrients. Some salts, such as alkaline citrate and succinate, are 

 favourable. Sumach tannin assists the formation of slime on agar 

 media. The optimum temperature is 17° C. Gum acacia has not a 

 cellulose origin, but is formed from levulose and maltose. The flux 

 produced by inoculating peach-trees with Bad. acacm is a metarabin 

 gum. The host-plant can convert Bad. acacm into Bad. metarabinum, 

 proving that the latter is a variety of the former producing an insoluble 

 gum. This explains the uniformity of the gums from certain species 

 of trees. 



Bacterial Disease of Cauliflower.! — F. C. Harrison describes a 

 disease of the cauliflower and allied plants, due to the action of Bacillus 

 oleracece. The bacillus varies considerably in length (1-4 /*) according 

 to the medium on which it is cultivated and to the host on which it is 

 found. The ends are always rounded : it is usually single, but short 

 chains occasionally occur. It possesses 7-18 peritrichous flagella. It 

 does not form spores, is easily stained, but not by Gram's method. 

 It grows well on most artificial media, the optimum temperature being 

 about 30° C. It is a potential anaerobe, but grows better in the 

 presence of oxygen. It produces acid ; ammonia ; hydrogen sulphide ; 

 a characteristic odour ; and enzymes. Of these latter the most interest- 

 ing is a cytase which has the power of destroying the cell-wall of various 

 plants. 



* Proc. I. inn. Soc. N.S.W., xxix. (1904) pp. 217-52 (2 pis.). 



t Centralbl. Bakt., 2 le Abt., xiii. (1904) pp. 46-55, 185-98 (6 pis.). 



H -2 



