323 
It appeared not improbable therefore that in the latter case the 
death of the tree might have resulted from the combined effect 
of the poisoning of the leaves, and the clogging of the tracheae, 
by morbid products arising from the cells of the medullary 
rays and wood-parenchyma which had been killed by the Botrytis. 
This hypothesis would reasonably correlate the presence of the 
diseased zone of the tree with the symptoms of rapid and extreme 
* Weber, C. A. Ueber den Einfluss héherer Temperaturen zu leiten, Ber. 
d. Deutsch Bot. Gesell. Bd. 3, 1885. 
‘ Dixon, H. H. Transpiration and the Ascent of Sap in Plants, London, 
1914, 
Dixon, H. H. : loc. cit. 
