310 



Scientific Proceedings (130) 



seems safe to conclude that the cold simply reveals the "poten- 

 tialities," so to speak, of the "bent" genes, and that these po- 

 tentialities are similar in the two species. 



151 (2111) 



Localization of the vomiting center. 

 By SOMA WEISS AND ROBERT A. HATCHER. 



[From the Cornell University Medical College, New York City.] 



1. Emesis was induced after destruction of the quadrigemi- 

 nate bodies, after destruction of the cerebellum, and after sec- 

 tion of the columns of Goll and Burdach in the cat, and after 

 destruction of the area described as the vomiting center by 

 Thumas 1 in the cat and in the dog. 



2. Emesis could not be induced by any drug that we em- 

 ployed after destruction of the sensory nuclei of the vagi in the 

 cat, nor could it be induced in any of three experiments in this 

 animal in which the sensory nucleus of only one side had been 

 destroyed, but vomiting did occur in one experiment in which an 

 attempt to destroy the sensory nucleus of the right vagus may 

 have been only partially successful. 



3. Results of these experiments indicate that the sensory 

 nuclei of the vagi are essential for the coordination of the vomit- 

 ing reflex (that is, for vomiting however induced), and this is in 

 harmony with our conception of the mechanism of emesis be- 

 cause : (a) It is well know that the vagus nerve is essential for 

 emetic action of many drugs, (b) We have been unable to in- 

 duce vomiting in the cat after destruction of the sensory nuclei 

 of the vagi while taking especial care to avoid injury to the area 

 described by Thumas as the vomiting center, (c) There are 

 no nerve cells concerned so far as known, in the area described 

 by Thumas. 



4. We have shown elsewhere 2 that afferent emetic impulses 

 from the heart pass by way of the sympathetic nerve, hence the 

 conclusion is unavoidable that this nerve must make functional 

 communication with the sensory nuclei of the vagi. 



1 Thumas, L. J., Arch. f. Anat. u. Phys., 1891, cxxiii, 44. 



2 Hatcher, R. A., and Weiss, Soma, Arch. Int. Med., 1922, vol. xxix, 690. 



