PHYSIOLOGY. 109 



of the motions of the os hyoides, which is a principal means of 

 thrusting the bolus into the pharynx ; of all these actions 

 most persons are as ignorant as they are of the motions of 

 the stomach and the intestines ; but what we will, is no more 

 than this, to swallow over drink as well as solid food ; and we 

 not only do it from the appetite being present, but from the 

 pleasure that meat and drink give to our palate. When a per- 

 son has no appetite he may be persuaded to take food into his 

 mouth, but he has a difficulty in swallowing it, which is not 

 felt when it is swallowed with an appetite ; he turns the 

 morsel in his mouth more than an hundred times over, and still 

 the fauces admit it most reluctantly ; and frequently after one- 

 fourth of an hour's chewing it is rejected, so that these mo- 

 tions are evidently instinctive, and strictly connected with the 

 desire that excited them." 



5. By certain PROPENSITIES or desires to remove an uneasy 

 or painful sensation, in consequence of which motions are ex- 

 cited, which are not directed to any external object, but confin- 

 ed to the body itself. 



These motions are not foreseen ; nor are we ever conscious 

 of willing any thing but the general effect. Of this kind, the 

 chief are the motions of sneezing, coughing, sighing, hiccuping, 

 vomiting, voiding urine and faeces, yawning, stretching, (pan- 

 diculatio,) and those motions of restlessness and inquietude 

 which pain and uneasiness produce. Weeping and laughing 

 are expressions of emotion and passion. " I say that these 

 motions are unforeseen ; but of the truth of this proposition I 

 am not certain. In these motions we at first do not know what 

 will follow. As a sickness may take place without vomiting, I 

 imagine that, in the first beginning of a nausea, if it was the 

 first instance of our experience, we could not know that vomit- 

 ing was to follow: it appears, therefore, that this motion is 

 merely instinctive. But, independently of this,, the instinctive 

 nature of these motions is sufficiently proved by the other part 

 of the proposition : for are we ever conscious of willing any thing 

 but the general effect in sneezing, in coughing, and still more 

 remarkably in hiccup, which is not yet explained, or even dis- 

 puted about ? 



" With propensities, we are in danger of confounding several 





