BY R. GREIG SMITH. 861 



same time a separation of the gum from the bacterial cells and 

 coagulated albuminoids. The filtered solution of the gum was 

 precipitated with alcohol, and the process was repeated until the 

 gum mucilage was free from reducing sugars. The gum formed 

 a thick mucilage with water and gave the reactions for arabin 

 with the usual reagents. During the purification, it w^as noted 

 that the slime was not so easily coagulated by alcohol as arabin. 

 The mucilage was also thicker and rather more gelatinous than 

 the mucilage made with a similar quantity of arabin and water. 

 So far the gum was identical with that yielded by Bac. pseud- 

 cn^ahinus. 



The gum was hydrolysed by boiling with 4 % sulphuric acid 

 for eight hours, and the neutral solution of reducing substances 

 was treated with phenylhydrazine-acetic acid mixture on the 

 water-bath. The crude osazone was purified and subsequently 

 recognised by its appearance and melting point as galactosazone. 

 No arabinosazone could be detected. The gum w^as therefore a 

 galactan. 



When the organism was grown side by side with Bac. jjseud- 

 arabinus, the cultural characters of the two bacteria were seen 

 to be identical, excepting that the cultures of the bacterium 

 from the Sugar-Cane were always white and that from the Quince 

 always yellow, varying from a pale buff on gelatine to a deep 

 yellow on potato. 



The bacillus probably has nothing to do with the production 

 of the mucilage of the Quince. I have tested Quince-mucilage, 

 and have found that it is coagulated with most reagents and that 

 it is not hydrolysed when boiled with 5% sulphuric acid for eight 

 hours. Quince-mucilage is therefore quite different from this 

 arabin-like galactan. 



One frequently finds that certain organisms, obtained from 

 natural sources, change colour upon cultivation within a few 

 months. For example, among the water-bacteria many w^hich 

 are white when isolated become yellow under cultivation, and 

 organisms originally producing red or violet colonies lose the 

 power of forming colour. Among the slime or gum bacteria, I 



56 y\y-i ' 



