222 THE LAWS OF ORGANIC 



tion of gastric juice, will be considered in the 

 next chapter. 



CCL. The different conditions of the mind 

 have been known, from the earliest observa- 

 tions, to excite or depress the digestive and 

 assimilating organs ; but as this subject is fully 

 treated of in a subsequent chapter, it is unneces- 

 sary, at present, to make any remarks upon it. 



CCLI. It has been observed by every one who 

 has paid particular attention to the division of the 

 par vagum, that great difficulty of breathing im- 

 mediately follows this operation, if performed on 

 both sides, or if the nerves be tied; and although 

 this effect was so obvious, the cause was not accu- 

 rately ascertained till LEGALLOIS proved it by di- 

 rect experiment. It was demonstrated that, when 

 the par vagum was divided, the superior and in- 

 ferior laryngeal branches, distributed to the muscles 

 of the larynx, no longer enabled them, as in 

 health, to open and close the glottis, the conse- 

 quence of which is, that atmospheric air can- 

 not pass in its usual quantity into the chest to 

 produce the ordinary changes of the blood. Al- 

 though the correctness of this explanation has 

 never been questioned, yet a variety of opinions 

 have been entertained in regard to the cause of 

 death.* DUPUYTREN supposed that the air 

 entered the lungs, but did not properly oxygen- 



t 

 * Vide pages 180-1, 200, 2C2, 224, 235, LEGALLOIS. 



