PNEUMOGASTKIC NERVES. 211 



The right pneumogastric, situated posteriorly, at the 

 cesophageal opening of the diaphragm, sends a few filaments 

 to the muscular coat and the mucous membrane of the 

 stomach, passes backward, and is distributed to the liver, 

 spleen, kidneys, suprarenal capsules, and finally to the whole 

 of the small intestine. 



The branches to the small intestine are very important. 

 These were accurately described in 1860, by Kollmann, in 

 an elaborate and beautifully-illustrated prize-essay. In the 

 plate showing the distribution of this nerve, it is seen that 

 the branches to the intestine are very numerous. Accord- 

 ing to these researches, the branches described belong to the 

 pneumogastric itself, and are not derived from the sympa- 

 thetic. 1 When we come to treat of the action of the pneu- 

 mogastric upon the small intestine, it will be seen that the 

 anatomical researches by Kollmann are fully confirmed by 

 physiological experiments. Before the nerves pass to the 

 intestines, there is a free anastomosis and interchange of 

 filaments between the right and the left pneumogastric. 



Properties and Functions of the Pneumogastric Nerves. 



There is no nerve in the body that has been the subject 

 of so many experiments, and concerning which so much has 

 been written, as the pneumogastric. Its accessible position 

 in many parts of its course, its extensive connections with 

 the digestive, the respiratory, and the circulatory system, 

 and the evident importance of its relations, have rendered 

 the literature connected with its physiology somewhat redun- 

 dant. We do not propose to discuss in full all of the views 

 entertained from time to time with regard to its functions, 

 but to state merely what seem to be well-ascertained facts, 

 and the most reasonable inferences, where the facts are diffi- 



1 KOLLMANN, Ueber den Verlauf des Lungenmagennerven in der Bauchhole. 

 Mne Prdsschrift. Zeitschrift fur wissenschafiliche Zoologie, Leipzig, 1860, Bd. x., 

 S. 413, et seq. 



