1885.] On the transpindion-stream in cat branches. 



(i) Sawed through ^ of diameter, at 24 cm. from base 



(") 



Oppo- 



In both these cases it is clear that the second cuts produce 

 great depression in the rates of absorption, though the effect 

 produced by the first cut is different in the two cases; in the second 

 may be seen the absence of the recovery which occurs in the 

 transpiration-stream after incisions have been made. 



In the following experiments, the suction was applied by a 

 Sprengel pump to the upper end of the branch, which was 

 covered by a few centimeters of water. 



Exp. 29. August 21, 1885. A branch of Sycamore (cut 

 under water) about 30 cm. in length was used. The current of 

 water was estimated by weighing the amounts of water sucked 

 up by the branch in given intervals of time. 



Gramms. 

 Intact branch transmitted in half an hour (Suction 



= 17*5 to 18*5 cm. of mercury) 



After two incisions T 7 ^- and ^* of diameter, it 

 transmitted in half an hour (Suction — 18 - 5 to 

 1 9 cm. of mercury) 



Exp. 30. Lilac (Syringa). August 21, 1885. 

 59 cm. in length, cut under water. 



Intact branch transmitted in |- hr. under a sucking 

 force of 1 6 cm. of mercury 



After two incisions had been made, it transmitted 

 1 '11 gr. in 2 hrs. i.e. per ^ hr 



The incisions (2 cm. apart) were each -^ of diameter, 

 and were at 23 cm. and 25 cm. from the base. 



2-14 



0-63 



A branch 



Gramms. 



0-28 



Exp. 31. Sycamore, cut under water, Aug. 24, 1885. 



Intact branch transmitted per half hour under a 

 sucking force of 1 7 cm. of mercury 



After two incisions had been made it transmitted, 

 per half hour 



Gramms. 

 6-59 

 0-23 



13 - 5 cm. and 15 cm. from the base. 



