CLASS 1. 2. 4. 1. OF IRRITATION. 105 



the glans penis. If its stimulus be greater, it then induces pain 

 at the neck of the bladder. The concretions of bile, which are 

 protruded into the neck of the gall-badder, when the disease is 

 not very great, produce pain at the other extremity of the bile- 

 duet, which enters the duodenum immediately under the pit of 

 the stomach; but, when the disease is great from the largeness of 

 the bile-stone, the pain is felt in the region of the liver at the 

 neck of the gall-bladder. 



It appears from hence, that the pains enumerated in this genus 

 are consequences of the inactivity of the organ; and, as they do 

 not occasion other diseases, should be classed according to their 

 proximate cause, which is, defective irritation; there are never- 

 theless other pains from defect of stimulus, which produce con- 

 vulsions, and belong to Class III. 1.1.; and others, which pro- 

 duce pains of some distant part by association, and belong to 

 Class IV. 2. 2. 



SPECIES. 



1. Sitis. Thirst. The senses of thirst and of hunger seem 

 to have this connexion, that the former is situated at the upper 

 end, and the latter at the lower end of the same canal. One 

 about the pharinx, where the oesophagus opens into the mouth, 

 and the other about the cardia ventriculi, where it opens into the 

 stomach. The extremities of other canals have been shewn to 

 possess correspondent sensibilities, or irritabilities, as the two ends 

 of the urethra, and of the common gall-duct. See IV. 2. 2. 2. 

 and 4. 



The membrane of the upper end of the gullet becomes torpid, 

 and consequently painful, when there is a deficiency of aqueous 

 fluid in the general system; it then wants its proper stimulus. 

 In the same manner a want of the stimulus of more solid mate- 

 rials at the other end of the canal, which terminates in the sto- 

 mach, produces hunger; as mentioned in Sect. XIV. 8. The 

 proximate causes of both of them therefore consist in deficient 

 irritation, when they are considered as pains; because these pains 

 are in consequence of the inactivity of the organ, according to 

 the fifth law of animal causation. Sect. IV. 5. But when they 

 are considered as desires, namely, of liquid or solid aliment, 

 their proximate cause consists in the pain of them, according to 

 the sixth law of animal causation. So the proximate cause of 

 the pain of coldness is the inactivity of the organ, and perhaps 

 the consequent accumulation of sensorial power in it; but the 

 pain itself or the consequent volition, is the proximate cause of 



VOL. II. P 



