From the Anatomical Laboratory, Johns Hopkins University 



EXPERIMENTS IN TRANSPLANTING LIMBS AND 

 THEIR BEARING UPON THE PROBLEMS OF 

 THE DEVELOPMENT OF NERVES^ 



ROSS GRANVILLE HARRISON 



• With Fourteen Figures 



Several years ago Braus described a series of ingenious experi- 

 ments in transplanting limbs of amphibian (Bombinator) larvae. 

 The experiments were made mainly for the purpose of inquiring 

 into questions relative to the development of peripheral nerves 

 and their author has interpreted his results in accordance with 

 Hensen's theory. Briefly stated this theory is that the nerve cen- 

 ters and their peripheral end-organs are connected from the begin- 

 ning of embryonic life by means of protoplasmic bridges, and that 

 the development of the nerve fiber consists merely in the differ- 

 entiation of these pre-existing connections under the stimulus of 

 functional activity. Banchi, whose results have, however, been 

 contradicted by Gemelli, has also made transplantation experi- 

 ments and like Braus has been led to the conclusion that the pe- 

 ripheral nerves develop in situ and that they may undergo their 

 development even when not connected with ganglion cells. My 

 own experiments lend, on the other hand, no support whatever 

 to the Hensen theory but show in agreement with His that the 

 nerve fiber is the outgrowth of the ganglion cell.^ It is this dif- 

 ference of opinion that has led to the following study, which is 



^A brief account of the experiments described below was given in a paper read before the Section in 

 Anatomy of the British Medical Association at the meeting held in Toronto, August 21-25, ^9°^- The 

 work was reported more fully to the Association of American Anatomists at the New York Meeting, 

 December 29, 1906. See Anatomical Record, Am. Journ. Anat., vol. vi, no. 3. 



-Harrison '04a, '06. 



The Journal of Experimental Zoology, vol. iv, no. 2. 



