186 DIGESTION. [CHAP. xxm. 



From the hinder border of the hard palate passes the soft palate, 

 a fold of mucous membrane enclosing mucous glands, a fibrous sub- 

 stratum, and several muscles by which it is capable of various mo- 

 tions. This terminates below by a free border, with the uvula in 

 the centre ; and from this border on each side descend the two 

 pillars of the soft palate : the posterior downwards and backwards, 

 enclosing and marking the course of the palato-pharyngeal muscle, 

 and dividing the alimentary compartment before alluded to from the 

 respiratory one above ; the anterior downwards and forwards, con- 

 taining the much-smaller palato-glossus muscle, and dividing the 

 same compartment from the mouth. Thus, this alimentary tract of 

 the pharynx may be said to have its upper part included within the 

 diverging pillars of the soft palate, with the tonsils projecting into 

 it, and to have its summit formed by the lower edge with the uvula, 

 the posterior or upper surface of the soft palate pertaining to the 

 respiratory tract, and the anterior or lower to the mouth. The 

 mucous membrane of the pharynx seen between the soft palate and 

 tongue on opening the mouth lies above the posterior pillars, and con- 

 sequently belongs to the respiratory compartment ; and we have on 

 several occasions had interesting proof of this in those cases of 

 chronic syphilis attended with a dry state of the pharyngeal mem- 

 brane, and in which this part has remained dry after the patient 

 has been made to swallow water. 



The alimentary compartment of the pharynx has four orifices, all 

 capable of closure : one towards the mouth, bounded by the lower 

 edge and anterior pillars of the palate, by the base of the tongue 

 and os hyoides ; another towards the oesophagus, at the lower bor- 

 der of the cricoid cartilage : these two are alimentary. The third 

 opening is towards the upper compartment, and is bounded by the 

 lower border of the palate with the uvula, and by the posterior 

 pillars with a portion of the posterior wall ; the fourth is towards 

 the lungs, and formed by the upper part of the larynx defended by 

 the epiglottis : these two are respiratory. The shape of the alimen- 

 tary compartment is very irregular, and capable of great alteration 

 by the movements partly of the os hyoides and tongue with the 

 larynx, and partly of the constrictor muscles forming its back and 

 sides. Much lax areolar tissue, containing no fat, surrounds it, and 

 allows of these movements on the contiguous parts. As it is im- 

 possible in the compass of this work to include a special description 

 of the muscles and other constituents of the pharynx, we must sup- 

 pose the reader to have already made himself acquainted with them 

 from the ordinary sources. 



