THE DEVELOPMENT OF THE SYMPATHETIC NERVOLS 
SYSTEM IN BIRDS.^'^ 
BY ALBERT KUNTZ, 
The present investigation of the development of the sympathetic 
nervous system in birds was undertaken in order to extend the writer’s 
observations on the histogenesis of the sympathetic nervous system in 
mammals, and to point out certain morphogenetic differences in the 
development of the sympathetic system in birds and mammals, with a 
view to their phylogenetic significance. 
In a recent paper'"'" the writer has reviewed the literature bearing on 
the development of the sympathetic nervous system. Therefore, only 
such references to the literature will be made in this paper as seem to 
be necessary. 
ffis, Jr. (’97)^=^^ called attention to the fact that in the chick two 
pairs of sympathetic trunks arise in the course of ontogeny. These he 
characterized as the ^‘primary” and the ‘'secondary” sympathetic 
trunks. According to his observations, the cells giving rise to l)oth the 
primary and the secondary sympathetic trunks are derived exclusively 
from the spinal ganglia. 
i\Iy observations on the morphogenesis of the sympathetic trunks in 
the chick do not differ essentially from those of His, Jr. I find, however, 
that the cells giving rise to the primary and the secondary sympathetic 
trunks in the chick, like those giving rise to the sympathetic trunks in 
mammals, are derived, wholly or in part from the neural tube. From 
the third to the sixth day of incubation, medullary cells may be observed 
migrating into the ventral nerve-roots in considerable numbers. With 
similar cells which wander out from the spinal ganglia, these cells 
migrate peripherally along the spinal nerves. At a point a little above 
the level of the aorta, some of these cells deviate from the course of 
the spinal nerves and wander toward the dorso-lateral surfaces of the 
aorta where they become aggregated and give rise to the primary sym- 
pathetic trunks. 
*From the Laboratories of Animal Biology of the State University of Iowa. 
**The Development of the Sympathetic Nervous System in Mammals. Jour. Comp. 
Neurol, and Psychol., Vol. 20, No. 3, pp. 211-258. 
***Ueber die Entwickelung des Bauchsympathicus beim Huhnchen und Menschen. 
Archiv. f. Anat. u. Entwg., Supplement, 1897. 
