CULTURAL CHARACTERS OF THE DAISY ORGANISM. 121 



MAXIMUM TEMPERATURE. 



The liigliest temperature at whicli growth will tale place is ±37° C. 

 Several slant agar cultures were made (some from a 3-day-old agar 

 culture, and others from a 9-day-old culture) and placed in a constant 

 temperature oven at 39° C. No growth occurred. At the end of 

 3 days at this temperature some of the cultures were removed and 

 kept at room temperature for 3 days, but no growth appeared. The 

 control tubes gave a good growth. This experiment was repeated 

 at 39° C. with the same result: No growth for 5 days, and none after 

 removal to room temperature (5 days more). 



Bouillon tubes were then inoculated and placed in a thermostat at 

 40° C, the controls being kept at room temperature. The controls 

 grew. The tubes in the thermostat remained clear (6 days). Plates 

 were then poured from them with negative results. 



In another experiment glycerine agar streak cultures failed to 

 grow at 37° C, but check tubes grew readily at room temperatures. 

 The indications from these experiments are that a temperature of 

 39° to 40° C. soon destroj^s the life of this organism— under the con- 

 ditions named. The following experiments were also made: 



In March, 1910, in a well-regulated thermostat, carefully controlled, 

 some very precise results were obtained confirming and extending 

 the earlier observations. The temperature during the first 4 days 

 ranged from 37° to 37.2° C. During the next 4 days the temper- 

 ature increased a trifle, ranging from 37.2° to 37.5° C. This ther- 

 mometer was compared Avith a standard instrument caKbrated at 

 the Reichs Anstalt in Berlin. 



The experiment was begun at 9.45 a. m. March 1, by inoculating 

 four +14 peptonized beef agar slants and 6 tubes of +15 pepto- 

 nized beef bouillon fi'om a peptone beef bouillon culture of February 

 26: One 3-mm. loopof the fluid was used for each agar slant and two 

 3-mm. loops for each tube of bouillon. One of the inoculated tubes 

 of bouillon was kept at room temperature as a check and the other 

 tubes were placed in the thermostat. At the end of 24 hours the 

 tube at room temperature showed a moderate amount of growth. 

 At the end of 48 hours there was a good growth in the check tube, 

 but none in any of the 9 tubes exposed in the thermostat. At noon 

 of ^larch 4 there was still no growth in the thermostat. The same was 

 true on March 7. On March 4, at noon, 1 tube of beef broth and 1 

 of agar w-ere removed from the thermostat and put at room tempera- 

 ture. On March 5 at 3 p. m. another tube of beef broth and 1 of 

 agar were removed from the thermostat. On March 7 at 11 a. m. 

 the remaining tubes (3 beef bouillon, 2 agar) were removed from the 

 thermostat. 



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