MECHANIC DEVELOPMENT OF PATHOLOGIC TISSUES 405 



cell in nuclear material the greater becomes its volume. Equally re- 

 markable discoveries were made in an investigation of the action of tis- 

 sues and organs upon one another. Vochting has produced a bending 

 growth in the root of the kohlrabi by removal of the leaves of one 

 side of the plant, so that the development of the normal side was 

 markedly greater than that of the other. The same effect was secured 

 in the petiole of a compound leaf of Ptclea mollis by removal of a lateral 

 leaflet and the result of this experiment is displayed in the accompany- 

 ing figure. Narcotics and the vitiation of the atmosphere by poisonous 

 gases inhibit growth in length. Mathuse figures the effect of removal 

 of the growing point of a plant in the promotion of superficial leaf 

 growth and other anatomic changes in the leaves of Ackyrantkes 

 Verschaffeltii. Other experiments of a somewhat similar nature are 

 equally illustrative. Hardly a more important and inviting field of 

 research has been opened than that which has been revealed by the 

 investigation of the experimental plant morphologists, or the experi- 

 mental pathologic plant anatomists. 



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