103 



broth wa8 used in making the inoculation, and there was plenty of water in the bot- 

 tom of the tube. After 7 days this tube was removed from the thermostat and kept 

 in the dark at room temperatures for 38 days, but no growth ensued. 



(8) Three well-plugged tubes of 1:2 moderately litmus alkaline beef broth (stock 

 245) were inoculated at the same time from the same tube, and in the same way. 

 Two of these were put into tlie thermcjstat at 40=' C. and the other was kept at room 

 temperatures. 



Result: The check tul)e clouded on the fourth day and i)assed through a normal 

 course of develoimient. The tubes in the thermostat remained perfectly clear until 

 the end of the experiment (45 days). 



(4) Three tubes of cauliflower broth (stock 217 ), whicli l)y long standing had dried 

 out one-fifth (2c.c.), were also inoculated at the same time from the same culture 

 and in the same way. Two of these tubes were kept at room temperatures and the 

 third was put into the thermostat at 40° C. 



Result: One of the check tubes clouded on the third day, the other some time 

 between the fourth and seventh day. Both developed a yellow pellicle and threw 

 down a yellow precipitate. The tul)e in the thermostat was imder observation 45 

 days, but there was no growth. 



(5) Three tubes of 1:2 acid beef broth (stock 204) were each inoculated with a 

 large loop from a beef -broth culture of Ps. hyaciMhl 7 days old. This culture, which 

 was moderately cloudy, showed many small zoogloeje floating in the fluid, and on 

 the bottom a small amount of decidedly yellow precipitate. Two of these tubes 

 were put into the thermostat at 36° to 38° C. and the third was kept at room tem- 

 peratures (mostly 21°). 



Result: On the third day the check tube became feebly clouded and contained 

 many tiny zoogkwe. On the eleventh day this tube was moderately cloudy, showed 

 a yellow precipitate, and bore on the wall of the tube at the surface of the fluid a 

 yellow rim of loosely adhering zooglo^a?. An agar culture inoculated from the same 

 tube at the same time and kept at room temperatures also developed normally. 

 The tubes in the thermostat remained free from bacterial growth as long as the 

 experiment continued (22 days). 



(6) Three tubes of resistant glass, each containing 10 c. c. of strongly alkaline beef 

 broth (stock 286b, neutral to phenolphthalein), in which Px. Iti/aciritlti was known to 

 grow well, were each inoculated with a loop from a clouded tube of alkaline beef 

 broth days old. After remaining for an hour at room temperatures, 2 of these 

 tubes were put into the thermostat and kept at 35° to 36.35° C. during the first 5 days, 

 then at 32° to 33.50° for 24 hours, and afterwards at 34. 15° to 35.35°. The third tube 

 was kept m the dark at rtjom temperatures ranging from 18° to 23° C, except on one 

 day when the room temperature fell to 8° C. Each of the tubes put into the thermo- 

 stat received a large loop of the cloudy l)roth; the tube left at room temperatures 

 received a smaller loo]i of this liroth, i. e., not one-fourth as many germs. 



Result: In 43 liours the (-heck tube was distinctly clouded. On the fourth day it 

 was well cloude<l, free from zooglcea;, and showed some yellow precipitate. The 

 other 2 tubes remained clear as long as they were left in the tliermostat. One was 

 removed on the thirteenth day and left for 24 days at room temperatures (mostly 

 22° C), but no growth ensued. Tlie other was removed on the sixth day and left at 

 room temperatures 31 days, but no growth ensued. At the close of the experiment 

 the tubes still contained 8 c. c. of ])roth, i. e., the concentration was not beyond what 

 this organism bears ri'adily. 



(7) Tliree cylinders of sugar ))eet (stock 292) were inoculated at the same time 

 and from the same tube as the preceding, each tube rec-eiving a large loop of the 

 cloudy fluid. Two of these tubes were put into the tliermostat along with the beef 

 broth (6), and tlie third was kept at room temperatures. 



Result: The che<k tube showed no growth at the end of the fourth day, i. e., there 



