AUTHOR S ABSTRACT OF THIS PAPER ISSUED BY 

 THE BIBLIOGRAPHIC SERVICE, DECEMBER 15 



THE TRANSPLANTATION OF THE CEREBRAL 

 HEMISPHERES OF AMBLYSTOMA^ 



H. SAXTON BURR 



Anatomical Laboratory of The School of Medicine, Yale University 



NINE FIGURES 



An interesting phase of the problem of differentiation in the 

 central nervous system is that of the role played by functional 

 activity in the development of the neurone after the organ- 

 forming period has passed. Harrison, Lewis, Bell, and others 

 have shown that embryonic cells of the nervous system will 

 multiply and differentiate in strange surroundings, apparently 

 irrespective of their normal connections. In many instances the 

 differentiation simulated more or less completely the normal 

 morphology of the part from which the cells were taken. In 

 other words, not only was there a differentiation of embryonic 

 nerve cells into neurones, but also the neurones were grouped as 

 they are in the adult brain. Whether such nervous tissue passed 

 beyond the first period of differentiation into the second period 

 of growth has not been indicated. 



In the experimental study of the first phase in the history of 

 a neurone there has been no evidence to show whether or not 

 the neurone so differentiated was capable of functioning.% If 

 function in this particular instance means the transmission of 

 an impulse along the neuraxis, it is practically impossible to 

 determine positively whether neurones in strange^surroundings 

 and without their normal connections do transmit impulses*and 

 whether neurones so placed ever progress beyond the primary 

 differentiation phase into the growth phase. This being true, 

 it is necessary to determine w^hat the factor which stimulates 

 the neurone to further growth really is. Two possibilities suggest 



1 1 am indebted to the Loomis Research Fund of the Yale University School 

 of Medicine for the materials used in this series of experiments. 



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