212 ALBERT KUNTZ 



• I. INTRODUCTION 



The present investigation of the development of the sympa- 

 thetic nervous system in mammals was carried on in the labora- 

 tories of Animal Biology of the State University of Iowa, under the 

 direction of Prof. Gilbert L. Houser. 



Although much excellent work has been done on the develop- 

 ment of the sympathetic nervous system, our knowledge concern- 

 ing the sympathetic neurones and the relation of the sympathetic 

 to the central nervous system is still very meager. Our newer 

 conceptions of nerve-components and of the functional divisions 

 of the peripheral nervous system call for a re-investigation of the 

 development of the sympathetic system m order to bring this 

 division of the nervous system into harmony with established 

 facts. 



The present investigation was undertaken in order to further 

 exact knowledge concerning the histogenesis of the sympathetic 

 system, to establish the histogenetic relationships between the 

 sympathetic neurones and the neurones in the central nervous 

 system, and to correlate the sympathetic system with the other 

 functional divisions of the nervous system. The most iniportant 

 results achieved pertain to increased knowledge concerning the 

 histogenesis of the sympathetic system and its relation to the 

 central nervous system, and to the fact that the cardiac plexus 

 and the sympathetic plexuses in the walls of the visceral organs 

 are not derived from the sympathetic trunks, as has hitherto 

 been supposed, but have their origin in nervous elements which 

 migrate from the vagus ganglia and the walls of the hind-bniin 

 along the fibers of the vagi. During the progress of the work, two 

 preliminary papers were published (see Bibliography). 



It is a real pleasure to express my deep sense of obligation to 

 Prof. Houser for his many helpful suggestions and for the inspira- 

 tion afforded by the constant enthusiastic interest manifested by 

 him during the progress of this investigation. I desire also to 

 express my indebtedness to Dr. F. A. Stromsten for many valua- 

 ble suggestions in technique. 



