206 DIGESTION. 



inattention, but is under the control of the will. The second 

 act is involuntary, when once commenced, but may be ex- 

 cited by the voluntary passage of solids or liquids beyond 

 the velum pendulum palati. It is impossible .to perform the 

 second act of deglutition unless there be some article, either 

 solid or liquid, in the pharynx. It is easy to make three or 

 four successful efforts consecutively, in which there is eleva- 

 tion of the larynx with all the other characteristic movements ; 

 but a little attention will show that with each act a small 

 quantity of saliva is swallowed. When the efforts have been 

 frequently repeated, the movements become impossible until 

 time enough has elapsed between them for the saliva to col- 

 lect. This fact was personally verified before writing this 

 paragraph; and it was demonstrated to be due to the ab- 

 sence of liquid ; for immediately after, an ounce of water 

 was swallowed without difficulty by sixteen successive move- 

 ments of deglutition. This experiment also shows the small 

 quantity of liquid (only half a drachm) necessary to excite 

 the contraction of the muscles concerned in the second act. 



All the movements of deglutition, except those of the first 

 period, must be regarded as essentially reflex, i. e., depending 

 upon an impression made upon the afferent nerves distrib- 

 uted to the mucoup membrane of the pharynx and oesopha- 

 gus. 1 



The position of the body has little to do with the facility 

 with which deglutition is effected. Liquids or solids may be 

 swallowed indifferently in all postures. Berard states that a 

 juggler, in his presence, passed an entire bottle of wine from 

 the mouth to the stomach, while standing on his head. 2 The 

 same feat we have lately seen accomplished with apparent 

 ease, by a juggler who drank three glasses of ale, while 

 standing on his hands in the inverted posture. 



1 The study of the connection of deglutition with the nervous system is de- 

 ferred until we come to treat specially, in another volume, of the functions of the 

 nerves. 



2 BERARD, Cours de Physiologic, Paris, 1849, tome ii., p. 32. 



