88 ROYAL SOCIETY OF CANADA 



Milk. — The whole milk began to turn sour and was viscous after 

 24 hours' growth. The acidity increased slowly, and after 4 or 5 

 days there was a soft coagulation. The coagulum. contracted a little 

 and pressed out some of the whey; both whey and coagulum were vis- 

 cous, the latter less than the former. As a rule, no serum was pressed 

 out, but some portions of the coagulum gradually cleared and formed 

 a grey, jelly-like, viscous mass. 



Beef houillon. — The bouillon became very turbid after 24 hours' 

 growth and a thick, grey pellicle formed. The broth gradually changed 

 into a jelly-like viscous mass, grey in colour, strongly offensive smell 

 and alkaline reaction. A copious sediment formed at the bottom of 

 the tube, which was slightly viscous but dissolved when shaken up. 



Whey louillon. — In whey bouillon no smell developed and the 

 reaction became slightly acid (from 24 hours on), and later was very 

 acid. With these exceptions, the culture behaved like the beef bouillon 

 one. 



Peptone solution, with or without salt. — In Dunham's solution good 

 growth occurred; the turbidity was most marked in the surface layers. 

 A copious, viscous sediment formed and the medium was slightly vis- 

 cous from 24 hours on. The reaction was not changed and there was 

 only a slight smell. 



Peptone solution 1 per cent -\- lactose 4 per cent, -\- dextrose 4 per 

 cent, or -{- maltose 4 per cent. In 24 hours there was diffuse turbidity, 

 more pronounced in the surface layers. The cultures were quite vis- 

 cous, and after three days the reaction in all tubes turned slowly acid; 

 a copious, grey sediment formed and the smell was disagreeable. The 

 viscosity in very acid cultures disappeared. 



Peptone solution 1 per cent, + saccharose 4 per cent, or -f glycerine 

 4 per cent. These cultures were very turbid in 24 hours, the surface 

 layers were very viscous, copious sediments formed, but there was no 

 change in the reaction of the media. 



No indol formed in peptone solution. 

 Growth occurred only in the presence of ox}'gen. 

 The optimum temperature for growth was 25° C, good growth 

 also at 15° to 20° C, and at 37.5° C. 



The best growth was in slightly sour or slightly alkaline media. 

 The thermal death point was 62° C. for 10 minutes for both old 

 and young cultures. 10 minutes at 60° C. usually killed old and 

 young cultures, but not always. 



Coverglass preparations kept in broad daylight lived for 3 weeks. 

 Milk and asrar cultures died out in 4 months. 



