SUMMARY OF THE PNEUMOGASTRICS. 253 



spleen, kidneys, suprarenal capsules, and the whole of the 

 small intestine. 



The true filaments of origin of the pneumogastrics are 

 exclusively sensory, and the nerves contain no motor fila- 

 ments, except, those derived from their anastomoses. 



The sensory filaments of the auricular branches give sen- 

 sibility to the upper part of the external auditory meatus 

 and the membrana tympani. 



The motor filaments of the pharyngeal branches animate 

 the muscles of the pharynx. The sensory filaments are not 

 important in the reflex phenomena of deglutition, but prob- 

 ably contribute slightly to the general sensibility of the 

 pharynx. 



The superior laryngeal nerves give sensibility to the up- 

 per portion of the larynx. They are exquisitely sensitive, 

 and, by their reflex action, aid in closing the larynx to the 

 entrance of foreign substances, and in the production of the 

 movements of deglutition. Stimulation of these nerves pro- 

 duces movements of deglutition and arrests the action of the 

 diaphragm. They animate, also, the movements of the crico- 

 thyroid muscles. 



The inferior laryngeals contain chiefly motor filaments. 

 They embrace the filaments from the spinal accessories, which 

 preside over phonation. They also contain motor filaments 

 from other sources, which preside over the respiratory move- 

 ments of the glottis. Their division abolishes vocal sounds, 

 and, in young animals, causes death by suffocation, the glot- 

 tis being closed in inspiration. Galvanization of their cen- 

 tral ends, after division, generally produces movements of 

 deglutition and arrest of the action of the diaphragm. 



The action of the cardiac branches has been studied by 

 experiments upon the pneumogastrics in the cervical region. 

 Division of the pneumogastrics in the neck increases the 

 number of pulsations of the heart. Galvanization of the 

 peripheral ends, after division, arrests the heart's action in 

 diastole, and galvanization of the central ends has no effect 



