RY R. GREIG SMITH. 677 



The bacteriological examination of this interesting sample 

 showed that it contained the bacilli of the normal type in practi- 

 cally pure culture, there being one inert bacterium to every 

 ninety-nine active bacilli. 



It is apparent from the bacteriological examination of these 

 samples that the inversion is the direct result of the growth of 

 the bacillus which I have described in the previous paper and to 

 which the name of Bac. levaniformaiis has been given. Indeed 

 it was from these samples that the numerous races of the bacillus 

 were obtained. The organism has been already shown to be 

 capable of growing in solutions of cane sugar containing but a 

 trace of nitrogenous food, as for example in solutions containing 

 one- thousandth of a per cent, of peptone. When growing in this 

 poor medium it alters the sugar so much as to produce a visible 

 formation of gum in a few days. In view of this faculty of 

 growing in poor media and of the fact that an inversion of sugar 

 accompanies the growth, there can be no doubt that it is alone 

 responsible for the inversion of the crystals in bulk, and that the 

 chief condition for its growth is a more or less moist state of the 

 sugar and a warm temperature. 



It has been already noted that the relative formation of gum 

 levan is less and the inversion of sugar greater in poor nitrogenous 

 than in more nitrogenous solutions. In refined sugar cr3^stals 

 the amount of nitrogenous matter is infinitesimal, and it may be 

 that the gum-forming faculty is entirely in abeyance, since no 

 gum is found in such sugars.* 



But although this hypothesis may partially explain the absence 

 of gum in bulk sugar, there is another property of the gum 

 cultures that must be taken into account. During the prolonged 

 cultivation of the bacillus, the solutions of sugar which during 

 the height of the fermentation are white and opaque, gradually, 

 as time goes on, become more and more translucent. The gum 



* For example, the sample which had heavily inverted and which con- 

 tained 26"3 % reducing sugar had only 0"19 % of gum and insoluble organic 

 matter precipitable by alcohol. 



