112 ROYAL SOCIETY OF CANADA 



Both lets were tubed and sterilized in steam. In whey with pepton'3 

 the growth at 18 to 22° C. was much as in Dunham's solution w^th 

 sucrose 5^ but more copious. Cultures were soon very slimy. An abim- 

 dant ropy sediment accumulated in the bottom of the tube, a heavy 

 slimy ring and a film formed at the surface and slimy filaments de 

 pended from the surface to the bottom. A strong green-blue pigment 

 developed and the surface layer became bright blue. 



In the whey without peptone there was abundant slimy gro^vth but 

 no ring nor film and no pigment. 



Growth on Potato at 18° to 22° C. — The half cylinders of sterilized 

 potato in test tubes showed growth in 24 hours and pigment in from 

 24 to 40 hours, depending on the amount of inoculating material. After 

 two days growth increased rapidly to a yellowdsh white, raised, wet- 

 shining, slimy band, sharply defined at the border. In 7 to 12 days 

 this gro\\''th covered the whole surface of the potato with a slimy layer. 

 The potato was rich in pigment in 24 to 48 hours, but the growth itself 

 showed no color or only traces of color for 4 or 5 days, and then became 

 blue-gray or light blue while the potato was bright blue or dark blue. 



The pigment appeared first as a green-blue tint in the potato. A 

 few hours later the color was light blue then bright blue and it had 

 penetrated through the cylinder of potato just above the water and 

 appeared as a blue spot on the opposite side. In 4 to 7 days the color 

 had spread through the whole mass of the potato above the water and 

 had turned a dark blue. The water in the bottom of the tube became 

 slimy, drawing out in threads, and occasionally it became bright blue. 

 After 12 days the pigment decreased to light blue and green-blue. First 

 the part of the potato beneath the surface of the liquid in the bottom 

 of the tube lost its pigment and became amber; this change progressed 

 upward and at length the whole cylinder was ochre j^ellow to rust color. 

 Some blue color, however, might remain in the upper part of the 

 potato. 



At 25° to 27° C. the growth and pigmentation were the same as 

 at 18° to 22° C. except as here noted. Color developed within 24 hours 

 and became as intense as at the lower temperature. The period of 

 pigmentation was shorter, lasting only 4 days and growth was a little 

 less copious. 



At 37° C. there was growth in 24 hours, increasing for 12 days, 

 but much less abundant than at the lower temperatures. No pigment 

 was produced at 37° C. 



Growth in Synthetic Media. — Tubes of Cohn's mannite medium, 

 Fermi's medium and Uschinsky's medium were inoculated and incu- 

 bated at 3 temperatures. 



