552 



Drs. T. L. Brunton and A. Macfadyen, 



1. Fats— Alkaline meat broth and olive oil, 2 per cent. 

 The results were negative. 



Experiments which were made by Manfredi* tend to show that fat- 

 containing media impair the vegetative energy of bacteria. 



2. Dextrose. — The culture fluid was prepared as follows : — 



Dextrose 2 per cent. 



Peptone 1 „ 



Sodic chloride .... 0*5 „ 



Reaction Neutral. 



After sterilisation, the flasks were inoculated with the scurf 

 bacillus and Welford bacillus. Incubated at 37° C. They were 

 examined on the fourth day. 



Febling's solution was no Longer reduced. The fluid gave a 

 marked acid reaction. 



The control solution reduced Fehling's solution. Reaction was 

 unchanged. 



3. Cane-sugar. — Cane-sugar, 2 per cent. 



Peptone, 1 per cent. 

 NaCl, -5 per cent. 

 Reaction, neutral. 



Inoculated with scurf bacillus and Welford bacillus, and incubated 

 at 37° C. 



The results were negative. "No reducing sugar detected. 



Muscle. — Alkaline meat broth cultures were used. Inoculated 

 with Finkler's spirillum and Welford bacillus. 



With the Welford bacillus a marked effect — the muscular tissue 

 becomes disintegrated, and the striae indistinct. 



These experiments, though incomplete in themselves, are sufficient 

 to show that the bacteria which liquefy gelatine and diastase starch, 

 can also exert a digestive influence on dextrose and muscle. The 

 exact determination of the products of this action in the case of 

 these and some other organic bodies must be reserved for further 

 investigation. 



To sum up briefly the results of this inquiry : — 



1. The bacteria which liquefy gelatine do so by means of a soluble 

 enzyme. 



2. This enzyme can be isolated, and its peptonising action demon- 

 strated apart from the microbes which produce it. 



3. The most active enzyme is that formed in meat broth. 



4. Acidity hinders, alkalinity favours its action. 



5. The bacteria which form a peptonising enzyme on proteid soil 

 can also produce a diastatic enzyme on carbohydrate soil. 



* ' Accademia dei Lincei, Rendiconti,' vol. 3, sem. 1, 1887, p. 535. 



