518 



CHAP. XXII. 



THE EXTERNAL SENSES IN GENERAL, AND TOUCH IN 

 PARTICULAR. 



" THE other office of the nerves we found to consist in com- 

 municating to the sensorium" (or organ of the mind) " the im- 

 pressions made by external objects. This is accomplished by the 

 external senses, which are, as it were, the watchmen of the body 

 and informers of the mind." 



The external senses are usually considered to be five : Touch, 

 taste, smell, sight, and hearing. But our feelings referrible to 

 sensation or consciousness are very numerous. Besides our 

 strictly mental feelings, we have a great variety of feelings in the 

 body at large. To say nothing of hunger and thirst, we may 

 feel weak or strong. The sensation of weakness is very distressing, 

 and often complained of in the epigastric region. The removal 

 of this makes us cognisant of a feeling of which otherwise 

 we think but little, a feeling of general support and mutual 

 elastic resistance, as it were, between all the particles of the 

 frame : and exhaustion makes us conscious of what was the com- 

 fort of this feeling. We feel the state of our muscles, whether 

 they are relaxed or contracted, or at least the position of the 

 parts which they move. We feel the state of tone or exhaustion 

 of muscles. We feel heat and cold in their various degrees, 

 pains, and endless uneasy sensations of distension, weight, prick- 

 ing, smarting, &c. &c., a large number of which are usually 

 referred to the sense of touch. But the sensation induced me- 

 chanically by the contact of something with us is properly called 

 touch. Forms of sensation may be peculiar to certain parts. 



" The five external senses alone belong to our present subject. 

 For to regard, with Gorter, the stimulus which inclines us to 

 relieve the intestines," &c., as so many distinct senses, is unne- 

 cessary minuteness, as Haller long since observed. 3 



' " J. De Gorter, Exercitatwnes Medico, iv. Amst. 1737. 4to." 



