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to the absence of larger veins as barriers in this region and 
secondly to a convergence of the veinlets into a more or less dis- 
tinct submarginal vein, running parallel to the leaf margin. Con- 
clusions from these experiments are not definite on this point, 
however, as the marginal strip was injured on the inner side only, 
the outer side, or leaf margin, being left uninjured. As a re- 
sult these outside strips were subjected to but half the possible 
water loss as compared with interior zones which had two cut 
edges. This point will be the basis of some experiments next 
year. Inside the marginal zones, just mentioned, there is con- 
siderable divergence of result depending upon width of strip, 
relation to basilar major veins, and larger veins crossing the 
strips. 
DISCUSSION 
These experimental wounds are of interest chiefly in compari- 
son with those induced by leaf-eating insects or larvae. In gen- 
eral, it would seem that the conditions imposed were often much 
more difficult than those likely to be encountered in nature. 
While leaves are often reduced to mere skeletons by such insect 
attacks, the period through which destruction takes place is 
greatly prolonged, thus permitting gradual adjustment, or it may 
occur only at night, allowing a number of hours for repair before 
the period of greater transpiration begins. 
In these experiments the wounds were all made at one time, 
the last but a few minutes later than the first. Conditions were 
rendered difficult also in that the wounds were inflicted early 
in the day and the leaves were promptly exposed to many hours 
of sunshine through the period of maximum transpiration. 
Whatever shock the plant might experience from such wounds 
was also augmented by the numerous and extensive lesions made 
at one time. Further, it should be noted, that in most of the 
wounds due to natural causes only the softer portion of the blade 
is eaten out by insects, leaving the veins uninjured, while in most 
of these experiments the major veins were partly or wholly des- 
troyed, leaving them as hindrances rather than aids to the leaf in 
its problem of readjustment. 
Freundlich^ has called attention to the possibility of regener- 
ation of vascular bundles in leaves through the enlargement of 
the smaller veins after the larger conducting channels have been 
interrupted. In these experiments there was no suggestion of 
1 Freundlich, H. F., Fntwicklung und Regeneration von Gefasbiindeln in Blatt- 
gebilden; Jahrb. f. wis. Bot., 46:137-206, 1908, 
