136 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



Is the water current arrested or slowed when the living 

 cells of the wood-parenchyma and medullary rays are 

 killed for a distance up the stem ? If so we have a 

 strong argument in support of Godlewski's theory. 



He accordingly killed all the living cells in a 

 given stretch of a normal branch by running hot 

 water round the latter while still attached to the tree 

 and provided with its foliage. 



After killing regions 1 5 to 20 cm. long by heating 

 them to 70 C for an hour, it was found that the 

 leaves above the tortured portion began to droop (in 

 the case of Fuchsia globosd] next day, and were all 

 dead and withered in five days. Syringa vulgaris 

 took longer to die, but the final result was the same. 



That this was due to the killing of the cells by the 

 hot water was concluded from the observation that 

 control plants remained fresh for a much longer time, 

 even when the whole of the cortex was removed over 

 the same stretch of branch. 



Hence Janse concluded that the medullary ray-cells 

 and the wood-parenchyma living, active cells 



wetek Schappen, 1885, pp. 11-24; Bot. Zeit. 1885, p. 302. See also 

 "Die Mitwirkung der Markstrahlen bei der Wasserbewegung im 

 Holze," Pringsheim's Jahrbiicher f. wiss. Bot. 1887, p. 1-69. And 

 Weber, " Ueber den Einfluss hoherer Ternperaturen auf die Fahig- 

 keit des Holzes den Transpirationsstrom zu leiten," Ber. d. d. bot. 

 Gesellsch. 1885, pp. 345-371. 



