302 MACDOUGAL AND SPOEHR— GROWTH AND IMBIBITION. 



Watered and record disturbed for 2 hours. 5 :oo P.M. Rate 

 7.8 mm. per day at 25° C. 



24, 8:00 A.M. Rate 5.7 mm. per day for previous 15 hours at 

 25° C. 



25, 8:00 A.M. Rate 6 mm. daily, 25° C. 



Control reset and as temperature of the body rose the rate cal- 

 culated in 2 hour intervals increased from 8.4 mm. at 27° C. to 

 9.6 mm. at 29° C. and 10.8 mm. at 29.5° C. 



26, 10:00 A.M. Rate was substantially maintained at 29° C, 

 being 9.6 mm. for the forenoon. 2:00 P.M. Rate 11.4 mm. daily, 

 31.5° C. 4:00 P.M. Rate 11.4 mm. daily, 32° C. 



22, 8:00 A.M. Rate 3.9 mm. daily at 17° C. 11:00 A.M. 

 Rate 5.8 mm. daily at 18° C. 10:00 P.M. Rate 3.8 mm. daily at 

 18° C. 



28, 8:00 A.M. Current on for higher temperature. 9:15 A.M. 

 Temperature of 32° C. was reached and 39° C. at 11 :30 A.M. One 

 hour later at 12:30 midday, the rate was 7.2 mm. per day at 39° C. 

 I :30 P.M. Rate 4.8 mm. per day at 40° C. 2 :30 P.M. Rate 3.6 

 mm. per day at 40° C. 3 :30 P.M. Rate 4.8 mm. per day at 40° C. 

 5:30 P.M. Rate 1.8 mm. per day at 41.5° C. 7:30 P.M. No 

 growth had taken place in the previous 2 hours. 9:30 P.M. Rate 

 of 3.6 mm. daily, the temperature having fallen to 36° C. 



Another shoot of the plant used in making the preceding record 

 being available, an auxograph was put in bearing with it when a 

 length of about 150 mm. had been reached on August 29, 1916. 

 The rate varied from about 15.6 mm. to 20.4 mm. daily at 35° C. 

 to 37° C. The temperature was raised from 36° C. to 47° C. in an 

 hour and a half on the third day, elongation stopping when this 

 point was reached. During the second hour and a half the tempera- 

 ture was allowed to fall to 43° C, growth being resumed above 43° 

 C. and continued at a rate varying from 10.8 mm. daily in the first 

 hour, 6.6 mm. daily during the following four hours, to 8.4 mm. 

 daily during the sixth hour. The temperature being raised to 46° 

 C. in twenty minutes, growth stopped at that point. Shortening 

 took place during the following hour and a half at temperatures of 

 46° C. to 48.5° C, but ceased as the temperature was brought back 

 to 44° C. at some point above that temperature. The shoot ap- 



