1885.] On the transpiration-stream in cut branches, 



365 



that the transpiration-stream can be hindered by treatment such 

 as bending or compressing the branch. 



Exp. 



water. 



38. Sept. 18, 1884. Bramble (Rubus sp.), cut under 



Time 

 1.0 



Rate 

 40-8 



bent to an angle of 20" 



3 



unbent 

 4 



34-8 



58-9 

 4.6 | 37-0 

 bent nearly parallel 



13 



unbent 

 15 

 26 



29-4 



50-2 

 37-7 



These experiments show that (i) bending does depress the rate 

 of absorption ; (ii) when the stem is straightened again, the rate is 

 temporarily quickened by the removal of the blocking caused by 

 the bend. 



Exp. 38. Continued Sept. 18, 1884. 



Time 

 4.44 



Rate 

 34-7 



Stem bent twice and tied closely in this position 



52 



unbent 



54 



56 



5.25 



18-5 



57-1 (?) 



44-6 



32-8 



The bending and straightening were again repeated with 

 precisely similar results, viz. : — 



Rate 



32-8 straight 

 18-5 bent 

 56-8 straight. 



These results confirm what was stated above. They are plainly 

 explicable on the theory that the transpiration- stream travels in the 

 cavities of the wood. 



They also confirm Russow's statements that bending does not 

 absolutely stop up the lumen of the vessels. 



