82 ■ ROYAL SOCIETY OF CANADA 



later it resembled muc-us. The growth was always thickest next to the 

 condensation water. 



Potato culture. — All 5 varieties gvQ\Y well on potatoes. In 24 

 hours at 25° C, a shiny growth developed and spread over the greater 

 part of the potato. The gro^i;h was thick, uneven, dirty-grey when 

 young, but became slightly brownish or yellowish with age, and was 

 very slimy. The growth either remained as a shiny, slimy-like mass, 

 or it dried into a dull grey paste. 



Milk cultures. — In all liquid media growth was first apparent in 

 the layers next the surface. In 24 hours the surface of milk cultures 

 became more or less slimy, but otherwise no change was visible, and 

 as far as could be seen, the lower layers of the milk were absolutely 

 unchanged. At 36 hours or later, the supernatant milk lost its white 

 colour, became clearer, and finally changed into a grey, transparent, 

 raucus-like mass. This layer increased gradually in thickness, until 

 the whole of the milk in the tube was a grey, translucent, jelly-like, 

 viscid mass. This took place in from 6 to 10 days. The milk never 

 underwent coagulation and the slimy mass w^as never entirely clear, but 

 always showed streaks of grey or white, which were probably a portion 

 of the less changed milk. In old cultures a copious, grey sediment was 

 deposited upon the bottom of the tube. At the end of a month, the 

 culture might be coherent, or might be a Jelly-like, non-viscid mass. 

 Old milk cultures were slightly alkaline, there was never any formation 

 of acid. 



Skim-milk and full milk behaved in the same way. In full milk, 

 however, the cream layer underwent the first change. 



Beef houillon and whey houillon cultures. — In 24 hours the surface 

 layer of the bouillon culture became very turbid and more or less slimy. 

 A greyish, thick, slimy ring formed at the surface, the deeper layers 

 of the bouillon were only slightly turbid and not slimy. On shaking 

 the culture the slimy surface growth could be gradually distributed in 

 the media, rendering it slightly slimy. Thread-like grey masses (Sta- 

 lactites) hung from the surface layer into the clearer bouillon. Soon 

 a copious sediment formed, which when shaken up dissolved slowly and 

 evenly. The reaction of the bouillon remained unchanged for a week, 

 and then became slightly alkaline; no odours developed. 



Peptone Solution. — In Dunham's solution and in peptone solution 

 without salt, the cultures behaved alike. A fairly copious growth ap- 

 peared, the surface growth was viscid, there was slight turbidity and 

 slight viscosity, and a fairly copious grey sediment formed, which be- 

 haved like the sediment in bouillon. The whole medium was never 

 changed into a jelly-like or slimy mass. The reaction never changed. 



