340 



Mr F. Darwin and Mr R. W. Phillips, [Nov. 23, 



It will be seen that the amount of effect in Exp. 2 is not so 

 great as in Exp. 1. The variability is due as we believe chiefly 

 to the difficulty of making the two saw-incisions exactly opposite. 

 In the following experiment the incisions were carefully made, 

 and we believed at the time that the whole of the vessels in the 

 cross section were severed. 



Exp. 3. July 27, 1885. 



(i) 



(^) 



p.m. 



5-26 



29 

 31 



48 

 52 

 54 



Kate 



84-7 



Sawed half through 



80-0 



78-1 



Sawed half through opposite to (i) 



29-4 



It was found afterwards upon careful examination that the 

 saw-cuts were not however exactly opposite, and that therefore 

 a very small strip of tissue remained unsevered. This no doubt 

 accounted for the somewhat slight effect produced by double 

 sawing. 



We therefore determined to make the incisions so deep as to 

 preclude this kind of error. The following experiment shows the 

 great effect of slightly deepening the saw-cuts. 



Exp. 4. 



The incisions* seemed only just to include the whole section 

 and certainly did not overlap. They were therefore both deepened 

 to 5 mm. (the branch being 8 mm. in diameter). The rate of 

 absorption immediately fell enormously. 



a. m . 

 11-22 



Rate 

 64 



* Incisions 5'5 cm. and 7*5 cm. respectively from the cut surface. 



