28 



Scientific Proceedings, Royal Dublin Society. 



pith, 0'16 em. Lower diam. of wood, 0-95 em.; of pith, 0'20 cm. Head, 

 24 cm. 



Table IT. 



At i. 20, picric acid was supplied to B, and forced through under a head 

 of 41 '5 cm. of mercury. At the same time, water was forced through A 

 under a head of 44 cm. of mercurj'. At i. 45, when the picric acid hnd 

 appeared in quantity at tlie lower end of B, tlie head of 24 em. of water 

 was restored to both. 



It will be seen that the mean rate of transmission before the high 

 pressure was applied was 0'450 g. and 0'469 g. per 10 min. for the control 

 and experimental branches respectively. During this time average tem- 

 perature was 11'8°. After the pressure was applied forcing distilled water 

 tlirough the control, and picric acid through the experimental branch, the 

 rates rose to 0'502 g. and 0"508 g. respectively for an average temperature of 

 12"0°. That is, the rate of transmission of the killed branch has increased by 

 8'3 per cent., while that of the living control lias increased by 11'5 per cent. 

 Probably the rise in both cases is due chiefly to the flushiug-out of the branch 



