BY R. GREIG SMITH. 625 



To this may be added the hackne3^ed suggestion of disinfecting 

 the premises and plant whenever possible. 



If the manufacturer desired to produce gum, he would use 

 such a saccharine fluid as cane juice, and after clarification infect 

 it with the bacillus. Then he would keep the juice as near 37° 

 C. as possible, but not much over that temperature, and certainly 

 not over 44° C. The juice would also be well aerated by tossing 

 or spraying, and finally the fermentation would be allowed to go 

 on until the maximum amount of gum had been formed. 

 Repeated infection during the process, as by running the juice 

 into dirty vessels, etc., would greatly assist the production. 

 With this knowledge of how to best produce gum, it is eas}^ to 

 see how the formation can best be prevented. 



To the intelligent manufacturer the knowledge of the cause is 

 enough to give the cue for its attempted elimination. Whether 

 this is possible, experience alone can show. Were it not for the 

 constant infection from without by the introduction of infected 

 material, the trouble might be overcome. Probably all the 

 manufacturer can hope for is a diminution of the gumming. The 

 microbe is exceedingly hard to kill. The vegetating forms must 

 be, to a certain extent, protected, during a part of their life at least, 

 by the gum capsules, and the spores can resist the action of 

 boiling water for at least five hours. But difficult as the task is, 

 it must be attempted so that the manifold changes which the 

 microbe induces may be minimised or prevented. 



EXPLANATION OF PLATE. 



The figures illustrate diagrammatically stages in the conversion of the 

 derived type of Bacilhis levani/ormans (right figures) to the normal type (left 

 figures). The medium, the number of the transfer or crop, and all colours 

 except white are noted. Shading indicates a dull appearance, absence of 

 shading shows that the culture had a glistening appearance when examined. 

 The two types were inoculated, incubated, and observed side by side. One- 

 half natural size. 



