I 



Scientific Proceedings. 



(223) 53 



carried out by Ludwig and Wild at about the middle of the last 

 century, it was found that ligation or transverse section of the 

 esophagus prevents the further progress of the peristalsis to the 

 lower segment. They drew the conclusion that the reflex is of a 

 local nature, that is, that the food or drink while passing the esoph- 

 agus sends up from each transversed section a sensory impulse 

 which causes a reflex contraction of that section. Some twenty- 

 five years later, however, A. Mosso made similar experiments and 

 obtained opposite results ; namely, that after ligating, transverse 

 cutting, and even after removing a whole ring of the esophagus, 

 the peristalsis once begun would appear also in the lower end of 

 the esophagus. Similar observations were made by Kronecker 

 and the author about 25 years ago on the cardia of rabbits. Even 

 after removal of a large part of the esophagus the cardia would 

 contract in due time after the beginning of swallowing. These ex- 

 periments seem to permit only one conclusion, namely, that there 

 are no local reflexes, that is, that the food while passing the esoph- 

 agus does not send up sensory impulses to the center of degluti- 

 tion, but that there is only one sensory impulse sent up at the begin- 

 ning of the act of deglutition which spreads slowly within the center 

 and sends down consecutively motor impulses to the successive 

 sections of the deglutition path. 



A few years ago the author reinvestigated the subject. There 

 was a direct contradiction in point of fact between Ludwig and 

 Wild on one hand, and Mosso and Kronecker and the author on 

 the other ; it seemed strange that Ludwig, the master physiologist, 

 should have failed to see what appeared so easy to observe. An 

 analysis of the methods employed in both series of investigations 

 led to discovery of the reason for the discrepancy in the results. 

 The animals of Ludwig and Wild were in deep anesthesia during 

 the experiments, while those of Mosso were out of the anesthesia 

 again, and the animals of the author's experiments were only under 

 slight anesthesia. The author tested this point on a few animals 

 and found the surmise correct. When the animals were in deep 

 anesthesia no peristalsis passed beneath a ligature, while it ran 

 down the entire esophagus as soon as the animals were out of the 

 anesthesia. This means that in normal animals the process of 

 deglutition is carried out by a reflex with only one initial sensory 



