306 MACDOUGAL AND SPOEHR— GROWTH AND IMBIBITION. 



daily, which decreased to 21.6 mm. daily at a temperature kept 

 within a narrow range at 35° C. This now being gradually raised 

 to 40° C. in a six hour interval the rate at first fell to 19.2 mm. daily, 

 then rose to 29 mm. daily, the maximum when measured at two 

 hour intervals. Almost any rise in temperature up to about 46° C. 

 seemed to be followed by a temporary acceleration in rate. 



Two younger shoots had arisen from the second Opimtia during 

 these tests and had attained a length of about 30 mm. during the 

 previous ten days. These were designated as " A " and " B." 



The temperature of these young shoots was between 25-45° C. 

 during most of this time, and for a few hours rose to 52° C. as 

 described in connection with the tests with other shoots. Separate 

 auxographs were put in bearing with the two shoots and ther- 

 mometers were arranged to take the temperature of the basal joint 

 from which they arose and of one of the other growing shoots 

 near by. 



The interest attached to the detail of the growth of these two 

 shoots warrants the transcription of the complete record. 



Sept. 



