TRANSPLANTATION OF HEMISPHERES 167 



SUMMARY 



The results of the series of operations may be summarized 

 as follows : 



1. Transplantation of the cerebral hemispheres indicates that 

 the factor which stimulates the growth phase of nervous develop- 

 ment is not the functional activity of the end organ, but rather 

 the ingrowth of peripheral neurones. 



2. In the transplanted hemisphere,the central gray is restricted 

 particularly in the regions of the nucleus medianus septi and in 

 the primordium hippocampi. 



3. The absence of ascending fibers reduces the size of the 

 lateral forebrain tract and practically prevents the formation 

 of the columna fornicis and the fimbria complex. 



4. A vascular pia mater is formed about the transplanted 

 hemisphere and a choroid plexus may be formed from properly 

 placed blood-vessels. 



LITERATURE CITED 



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Burr, H. S. 1916 The effect of the removal of the nasal placodes on Ambly- 

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1916 a Regeneration in the brain of Amblystoma. Jour. Comp. Neur., 

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Harrison, R. G. 1910 The outgrowth of the nerve fiber as a mode of proto- 

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Herrick, C. J. 1910 The morphology of the forebrain in Amphibia and Reptilia. 

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