Micro-organisms of Maple Sap 177 



IV. Physical axd Biochemical Features 



i. Gas production. — Gas production in maple sap and in 

 bouillon containing dextrose, sucrose, lactose, maltose, mannit, 

 and potato extract, but not in bouillon containing glycerin. Gas 

 composed of carbon dioxid and hydrogen. 



2. Growth in closed arm. — Occurred in fermentation tubes 

 of bouillon containing dextrose, sucrose, lactose, maltose, and 

 mannit, and in tubes of potato extract, but not in tubes of bouill. >n 

 containing glycerin. 



3. Acid production. — Acid formed in maple sap, and in 

 bouillon containing dextrose, sucrose, lactose, maltose, glycerin 

 and mannit. 



4. Ammonia production. — Moderate in bouillon. 



5. Nitrate reduction. — Nitrates reduced to nitrite-. 



6. Indol and phenol production. — Feeble to moderate indol 

 production in bouillon and in Dunham's solution. Phenol pro- 

 duction negative. 



7. Toleration of acids. — Medium growth in bouillon acidified 

 with HC1 to -f-25 Fuller's scale and in bouillon acidified to -4- 20 

 with acetic acid. 



8. Toleration of sodium hydroxid. — No growth in tubes 

 of bouillon having a reaction more alkaline than — 5 Fuller's scale. 

 The organism was not killed in tubes having an initial reaction 

 of — 25, since, after twelve days, when the alkali was neutralized 

 by atmospheric carbon dioxid, fair growth developed in such 

 tubes. A more alkaline initial reaction invariably killed the 

 organism. 



9. Optimum reaction. — For growth in bouillon the opti- 

 mum reaction was found to be +10 Fuller's scale. 



10. Vitality on culture media. — Transfers from old cultures 

 on various media, even when these had dried down, developed 

 promptly. 



11. 'Temperature relations. — Thermal death point in bouil- 

 lon (10 minutes' exposure in water bath in thin walled tubes! 



