No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 6 1 



pericellular plexuses ; each branch probably having such an 

 ending. 



3) The ending of the non-meduUated fibers in the ganglion 

 has not been determined definitely. 



Sympathetic Ganglia of Birds. 



The observations here recorded were made on half-grown 

 chickens. A i^ to 4^ solution of methylene blue in normal 

 salt was injected into the humeral vein (Owen), just above its 

 division over the distal end of the humerus. The methylene 

 blue was allowed to flow into the circulation as quickly as pos- 

 sible ; as in birds, a small quantity of the solution causes a 

 stoppage of the heart. At the expiration of thirty to forty 

 minutes the sternum with the attached muscles was removed, 

 and the heart and lungs displaced to one side. In this way the 

 dorsal sympathetic ganglia are readily exposed. In the chicken 

 the dorsal sympathetic ganglia rest on the spinal ganglia, so 

 that a white ramus as such is wanting. The sympathetic gan- 

 glia may, therefore, be best removed with the spinal ganglia ; 

 this was usually done. The tissues so removed were fixed in 

 ammonium molybdate, the further treatment being as previously 

 indicated. It should be stated at the outstart that the results 

 obtained on the sympathetic ganglia of birds has been far from 

 what might be desired. And this for two reasons : 



i) I have found it very difficult to stain these structures at 

 all well in methylene blue. Very generally, all the structures 

 of the ganglion stain a diffuse blue; in which case, sections 

 show scarcely more than may be seen in sections of these 

 ganglia stained with the ordinary stains. 



2) The few sections that were well stained would fade in a 

 few days or weeks, no matter what care was taken. In some 

 few instances, however, results which may be compared with 

 those obtained on other vertebrates have been at my disposal. 



In the literature I have been able to consult I find no refer- 

 ence to observations made on the sympathetic ganglia of birds 

 with the methylene blue method, although these ganglia have 

 been stained by Cajal (27), Retzius (28), and Lenhossek (29). 



