(172) 
member and i: is highly improbable that the injury stimulus 
played a considerable part because of the comparatively 
small injury, the rapid healing of the cut surface, and the 
long period of growth undisturbed by any further injury. 
With the exception of Pfeffer’s restriction of growth method 
as used by Hering, the present method seems to excel the 
others in all three of the above points. In the case where 
the growth is restricted by imbedding in gypsum it is not im- 
probable that the constant stimulus of the contact more than 
counterbalances the advantages of the method, and as Kny 
has pointed out the disturbance in nutrition must be a serious 
factor. * 
The interesting correlation between position and length as 
made out in Lupinus albus naturally brings up the various 
theories of the relation between the position of a leaflet in 
the leaf-system and its size. There are so many facts in 
other cases which go to disprove any connection between the 
directness of the path of nutrition and the size of a leaf that 
we are not justified in concluding that the first necessarily 
determines the second. In the present state of our knowl- 
edge it is perhaps safest not to rush too hastily into obviously 
mechanical explanations of the facts of regulation. 
The results obtained in the position regulations have so few 
other facts to serve for comparison that it is hard to get their 
bearings on general questions of morphology and physiology. 
The most superficial glance at the results is sufficient to show 
that the reactions cannot be explained on any obviously me- 
chanical basis. Nor can we explain them as direct results 
of the stimulus of the injury produced at the moment of the 
leaflet removal. They seem to be bound up with the internal 
correlations within the leaf-system itself and independent 
of any external factors. One very evident fact stands out 
ur months after my results were presented before the Botanical So- 
ciety of America, Professor Némec gave a paper dealing with the results of 
a similar investigation by himself in which he also found that the imbedding 
induced that it could not be used to advantage. [Némec, B 
Folgen einer Symmetriest6rung bei zusammengesetzten Blattern. (Pre- 
sented Nov. 14, 1902.) Bull. Internat. Acad. Sci., Bohéme, 1902. ] 
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