BY R. GREIG SMITH. 127 



to prevent the isolation of the latter. Again, the age of the 

 specimens from which the bacteria were obtained might have 

 much to do in bringing about the practical suppression of Bad. 

 metarahinum. 



One of the races of Bact. acacicb had, however, differed from 

 the normal type, and there was the possibility that this race 

 might produce an insoluble gum, so in order to test this point a 

 quantity of the slime was prepared. It was noted that the race 

 was very vigorous, and produced a good quantity of slime. The 

 pure gum acids, when taken from the alcoholic solution in which 

 they had been precipitated, dissolved readily in water. Drying 

 for several hours at 100° in the steam bath did not affect the 

 ready solubility, from which it is evident that the bacterium was 

 really a race of Bad. acacice. 



The investigation showed that the gum-flux of the plum was 

 due in part at least to the action of Bad. acacice. 



VI. — The Gum-flux of the Cedar. 



The gum-flux of the cedar has been already noted by Maiden,"^ 

 who thus describes the gum — "It is a very pale yellow gum . . . 

 swells largely in cold water, and in the course of 24 hours it 

 nearl}' wholly dissolves . . . leaving a small percentage of 

 metarabin." 



A few twigs of the red cedar, Cedrela australis, F.v'.M., bearing 

 small amber-coloured tears of gum were forwarded to me by Mr. 

 H. W. Potts, Principal of the ITawkesbury Agricultural College, 

 and in the letter which accompanied the samples he said, " They 

 were found on trees growing in Richmond. The gum appears to 

 exude in all cases at points attacked by some grub, possibly that 

 of the Red Cedar Moth, Bpicrosis." 



Portions of the twigs were passed rapidly through the bunsen- 

 flame to sterilise the outer surfaces, and were afterwards cut up 

 with a sterile knife and introduced into tubes of molten glucose 

 gelatine. Some of these tubes were poured into plates at once, 



"' Maiden, These Proceedings (2), iv. 1047. 



