454 



Profs. Percy Frankland and Marshall Ward. 



be inferred that the slowing was due to either (1) lack of accom- 

 modation, or (2) the greater variation of temperature. 



Then we find, after l hours at the temperatures given, the doub- 

 ling took 36 minutes at 34 to 35 a range of 1C. only which 

 certainly suggests that it is the temperature, and not the range 

 which is effective in slowing the growth. 



Next same culture, but having now been 5 hours at these 

 temperatures we find 54 and 56 minutes respectively necessary to 

 double the length at 34'25 to 37'75 C., a range of 3'5; and since the 

 same range was experienced by the first filament mentioned, but 

 which was measured during the first hour or so of exposure to these 

 temperatures, we can no longer doubt that the slowing is due to 

 the gradual effect of the temperature, and not to the range. 



This means that at the temperatures given the rate of growth 

 gradually slows, and the grand curve takes a shorter shape, and, on 

 consulting the previous series of curves, the same fact becomes 

 apparent. 



On November 9 spores were sown at 11.30 A.M. in 10 per cent, 

 gelatine, and put in at 22 C. ; at 6 P.M. they had germinated to 

 filaments over 100 ft long, and the culture was put into Sachs' box at 

 36 37 C. 



In order to see if any body, such as C0 2 , caused or hastened the 

 running down of the culture, I put a little KHO solution in one arm 

 of the cell, next the cotton-wool plug.* This was suggested by the 

 experiments of November 7, and previous observations on the extra- 

 ordinary irregularities and slowing of the growth at these high 

 temperatures. 



The measurements were as follows : 



* See also experiments on p. 443. 



Curve 157, p. 442. 



