BY R. GREIG SMITH. . 385 



portions were inserted into faintly acid saccharose-peptone media"*^ 

 and incubated at 30°. From the tubes of media that became 

 turbid, tubes of saccharose-peptone agar were infected and plates 

 prepared in the usual manner. The media infected with frag- 

 ments of heart-wood were sterile, but in cases where the bark 

 had been taken, two kinds of colonies developed. One of these 

 was in the minority, and will be referred to again in dealing with 

 the insoluble gums. The prevailing bacterium was stroked upon 

 saccharose agar, and the growth was found to contain capsulated 

 bacteria together with slimy bacterial clumps. A bacterium had 

 therefore been isolated which promised well for the research. 



A number of experimental cultures were then made with the 

 object of determining the constituents which might be employed 

 to construct a prescription for the manufacture of a medium that 

 would yield a maximum amount of slime and at the same time 

 enable one to trace the constituents from which the slime is 

 derived. The experiments, however, led to no useful result, 

 partly because too high a temperature (30°) was employed and 

 partly because a discrimination was not made between the 

 quantit}'^ of bacteria and the amount of slime. The question of 

 the slime-forming constituents will be discussed in a future paper. 

 On a peptone-saccharose agar medium, however, enough slime 

 was obtained to enable a few tests to be made. 



The slime, which adhered to the surface of the medium, was 

 moistened with water, and after it had swelled it was removed 

 with a rubber spade, the greatest care being taken to avoid 

 removing portions of the agar. 



The slimy emulsion was stirred with a few drops of dilute hydro- 

 chloric acid and precipitated with alcohol. The coagulum, on 

 treatment with water and then alcohol, produced an opalescent 

 solution from which the slime v/as precipitated by potassium 

 chloride. The watery emulsion was found to be free from 



*'' An improvement upon this method of isolation would be to employ 

 ordinary gkicose gelatine, in which the bacteria grow very well. Tubes of 

 molten glucose gelatine should be infected with the fragments of wood and 

 plates formed from these at once and after an incubation of 1, 2, 4, 8 and 24 

 hours at .30^. 



