88o 



per cent, less than in the undisturbed beets. Aderhold's^ experiments with 

 roots and grain gave similar results. It was found in grain that the length 

 of the heads was strongly affected, irrespective of the reduction of the whole 

 harvest. 



Nevertheless, one's fears should not carry one too far, nor should slight 

 losses of leaf substances be considered of too great importance as has 

 recently been estimated by many pathologists in judging the injury due to 

 fungi. It must not be forgotten that the parts of still vigorously growing 

 leaves, which have lost some of their lamina, are excited to increased effort, 

 as I have proved experimentally*. Boirivant'' found, in fact, that after the 

 removal of leaf blades the petioles and stems participate to a greater degree 

 than usual in the assimilation and that their parenchymatous tissue can 

 begin to elongate and increase. 



1 Aderhold, R., Ul)pr die duich teilweise Zerstorung- de.s Blattvverkes der Pflanze 

 zugrefiiglen Schaden. Prakt. Blatter f. Pflanzenbau u. Pflanzenschutz. Ill Jahrg-. 

 1905, Part 2. 



2 Sorauer, P. Studien iiber Verdunstung. Forsch. a. d. Gebiete der Agrrikultur- 

 physik. Vol. Ill, Part 4-5, p. 109. 



3 Boirivant, A., Sur les tissu assimilateur des tiges privees de feuilles. Just's 

 Bot. Jahresb. 1898, II, p. 231. 



