HuBER, Sympathetic Nervous System, 83 



His, Jr. (16) and Romberg were, I believe, the first to 

 draw attention to the fact that these cells were not simply split 

 off from the spinal ganglia, nor were they pushed out of the 

 ganglionic anlage as a result of a rapid proliferation of the 

 cells in these anlagen, as was held by the earlier investigators, but 

 that they migrated from the spinal ganglia into the surrounding 

 tissue. His, Jr. (11) describes these cells as wandering in 

 swarms, indistinctly bounded, toward the ventral portion of the 

 embryo. In the cervical and upper dorsal region, these migrat- 

 ing cells collect in larger groups on the dorsal side of the carot- 

 ids, in the abdominal region, by the side of the aorta, thus 

 forming, with the developing rami communicantes, above noted, 

 the anlagen for the great sympathetic cords or chains. 



At this early stage in the development of the sympathetic 

 system the great majority of the cells are as yet apolar, and many 

 show karyokinetic figures. From the groups of cells, forming 

 the anlagen of the ganglia of the chain, germinal cells wander 

 to a position below the aorta, to form the coelic and the other 

 ganglia found here. This wandering of the germ cells of sym- 

 pathetic ganglia from the anlagen of the spinal ganglia or the 

 larger ganglia of the chain to peripheral organs has been most 

 clearly shown for the ganglia found in the heart. His, Jr. (11) 

 has given us a very complete account of the way in which the 

 germ cells reach this organ. He has studied the development 

 of the heart nerves in fishes, amphibia and birds, also in the 

 human embryo. It would encroach too much on the time I 

 have set for this portion of my subject, to give a detailed account 

 of the results obtained by him ; I will therefore simply give the 

 following conclusions reached : "That the ganglia of the heart 

 are developed from germ cells which wander to this organ from 

 the spinal ganglia and the sympathetic ganglia. This migration 

 takes place by one of two paths : — in fishes and batrachians 

 along the veins, and in birds and mammals along the arteries." 



That the sympathetic ganglia which are found in connection 

 with some of the cranial nerves are developed in the same way 

 as are the ganglia of the great chains may be gathered from 

 observations made by Remak (17) on chicks, of the third day of 



