96 PHYSIOLOGY. 



preside over the formation and nutrition of the different 

 organs and tissues of the bod)| 



6. [Sensibility belongs exclusively to animals provided with 

 a nervous system) It enables us to receive impressions 

 from external objects, or from changes going on in our own 

 bodies ; and to the accuracy of this power, we owe our 

 ability to guard ourselves against the influence of noxious 

 agents. 



7. .' Sensibility may be divided into two kinds, general and 

 special^ By general sensibility is meant, that universal sense, 

 of which we are conscious over the whole body, in the 

 mouth, &c. The same also exists in the interior of the 

 body, and conveys to the mind a knowledge of the wants of 

 the system ; and when disease attacks any part, it immedi- 

 ately apprizes us of the danger, in order that we may take 

 early measures to remove itj (By special sensibility, we 

 mean that property which renders the eye sensible to light, 

 the ear to sound, &c. Every organ has its own special 

 sensibility 



8. (The brain is the common centre of sensibility, both 

 general and special) No impression can be felt on any part 

 or organ, unless it has a connection with the brain. If the 

 nerves going from that organ are divided, or if their function 

 is lost from palsy or any cause whatever, there can be no 

 sensation perceived, as none is excited. 



9. j|By perception is meant, the faculty which the brain 

 has of perceiving or taking notice of these impressions}! 

 Perception and thought then, are owing to the property of 

 matter, called sensibility. Without it, we would be like 

 stocks or stones, alike unconscious of pleasure or of pain. 



10. According to some physiologists, there, is another 

 kind of sensibility, which is termed organic. This resides 

 in the several internal organs, where it is called into exer- 

 cise, and does not require the action of the brain.) It de- 

 pends for nervous influence upon the great sympathetic nerve. 

 That such a kind of sensibility exists is very probable, but 



