PNEUMOGASTRIC NERVE. 473 



pulmonary engorgement, therefore, continue to increase, until the 

 lungs are so seriously altered and engorged that they are no longer 

 capable of transmitting the blood, and circulation and respiration 

 come to an end at the same time. 



It must be remembered, also, that the pneumogastric nerve has 

 other important distributions, beside those to the larynx and the 

 lungs; and the effect produced by its division upon these other 

 organs has no doubt a certain share in producing the results which 

 follow. Bearing in mind the very extensive distribution of the 

 pneumogastric nerve and the complicated character of its func- 

 tions, we may conclude that after section of this nerve death takes 

 place from a combination of various causes; the most active of 

 which is a peculiar engorgement of the lungs and imperfect per- 

 formance of the respiratory function. 



Stomach, and Digestive Function. After division of the pneumo- 

 gastric nerves, the sensations of hunger and thirst remain, and the 

 secretion of gastric juice continues. Nevertheless the digestive 

 function is disturbed in various ways, though not altogether abo- 

 lished. The appetite is more or less diminished, as it would be 

 after any serious operation, but it remains sufficiently active to 

 show that its existence is not directly dependent on the integrity of 

 the pneumogastric nerve. Digestion, however, very seldom takes 

 place, to any considerable extent, owing to the following circum- 

 stances : The animal is frequently seen to take food and drink with 

 considerable avidity ; but in a few moments afterward the food and 

 drink are suddenly rejected by a peculiar kind of regurgitation. 

 This regurgitation does not resemble the act of vomiting, but the 

 substances swallowed are again discharged so easily and instan- 

 taneously as to lead to the belief that they had never passed into 

 the stomach. Such, indeed, is actually the case, as any one may 

 convince himself by watching the process, which is often repeated 

 by the animal at short intervals. The food and drink, taken volun- 

 tarily, pass down into the oasophagus, but owing to the paralysis of 

 the muscular fibres of this canal, are not conveyed into the stomach. 

 They accumulate consequently in the lower and middle part of the 

 oesophagus ; and in a few moments are rejected by a sudden anti- 

 staltic action of the parts, excited, apparently, through the influence 

 of the great sympathetic. 



The muscular coat of the stomach is also paralyzed to a con- 

 siderable extent by section of this nerve. Longet has shown, by 

 introducing food artificially into the stomach, that gastric juice 



