292 



Bacteriologie. 



Smith, R.Greig, A Variable Galactan Bacterium. (Abstr. Proc. 

 linn. Soc. N. S. Wales. 1904.) 



A bacterium isolated from the tissues of a species of Strychnos 

 grew on gelatine as brittle moruloid colonies which contained an 

 insoluble gum. Cultivation at 30° C. caused the organism to rapidly 

 lose the faculty of forming this insoluble gum. A soluble gum was 

 produced instead, and the colonies in consequence became gummy 

 and otherwise uncharacteristic. The gums from both forms of bacteria 

 were galactans and differed only in solubility. Smith. 



Smith, R. Greig, A Yellow Race of Bacillus pseudarabinns from 

 the Quince. (Abstr. Proc. linn. Soc. N. S. Wales. 1904.) 



The organism is identical in its morphological and cultural 

 characters with the white race previously isolated from the Sugar- 

 Cane. The gum obtained from the slime was also identical in giving 

 the reactions of arabin and in yielding only galactose upon hydrolysis. 

 While the cultivations of the Sugar-Cane race were always white, 

 those of the Quince race were yellow. The races have maintained 

 their colour-characters during a year's subcultivation. Smith. 



Smith, R. Greig, The Bacterial Origin of Macrosartiia Gum. 



(Abstr. Proc. linn. Soc. N. S. Wales. 1904.) 



An organism, Bacillus inacrozamiae, n.sp., isolated from the 

 tissues of Macrosanna spiralis which was exuding a gum, produced, 

 upon levulose media, a slime from which a gum was obtained. The 

 bacterial gum, when prepared soon after the isolation of the organism, 

 differed slightly in its chemical reactions from the natural gum. 

 When prepared after an interval of six months, it diifered conside- 

 rably. The product of hydrolysis was constant and identical with that 

 furnished by the natural gum. This product yielded an osazone 

 melting ten degrees below galactosazone, while from the gum were 

 obtained furfural, mucic and oxalic acids. As the natural and bacterial 

 gums were practically identical when first examined, and probably 

 would have been identical if examined earlier, there can be no doubt 

 that the bacterium caused the gum-flux of the plant. Smith. 



Smith, R. Greig, The Bacterial Origin of the Gums of the 

 Arabin Group. (Abstr. Proc. linn. Soc. N. S. Wales. 1904.) 



XI. The Nutrition of Bact. acaciae. 



Bact. accaciae , the arabin-former, produces gum readity in the 

 presence of suitable nutrients. Levulose, Saccharose, maitose, mannite 

 and glycerine are sources of carbon; while dextrose, galactose, lactose 

 and raffinose are not. Dextrose or galactose prevents the gum being 

 formed from levulose or maitose. The organism acquires and readily 

 loses the power of utilising Saccharose. It temporarily loses the gum- 

 formingfaculty when subcultivated upon sugar-free media. The amides 

 are the best nitrogenous nutrients : a trace of asparagine (0.04 %) is 

 sufficient to produce half the maximum amount of gum. Salts may 



