DISTINCTNESS OP THE TWO POWERS. 139 



sensation and motion. This opinion was tested by ex- 

 periment. He divided it in an ass, and the jaw to which 

 it is distributed, instantly fell relaxed, and was deprived of 

 all sensibility. 



Emily. I should think his opinions were established 

 satisfactorily enough now. But what other functions 

 does the nervous power possess ? I think you mentioned 

 that these which we have already considered, are not 

 the only ones. 



Dr. B. It is known to possess some influence in the 

 process of secretion, for if the nerve be divided which is 

 distributed to a secreting organ, the secreting process 

 immediately ceases. How this influence is exerted, we 

 do not know. It is also inferred with a great deal of 

 reason, that the nervous power takes no small part in the 

 production of animal heat. 



Such are the functions of the nervous power ; and that 

 this power is perfectly different from the sensorial, is ca- 

 pable of unexceptionable proof. 



Emily. I am glad you have mentioned this, for I was 

 just about to ask you for more definite evidence of their 

 distinctness. We cannot distinguish between the im- 

 pression and the sensation they seem to be one and the 

 same act, and I confess, I see no evidence why they are 

 not both the result of one general power. 



-D**- B We know that they are distinct, because one 

 may continue in action while the other is destroyed, or 

 prevented from action. Thus, in some diseases or inju- 

 ries of the brain, volition, sensation, consciousness may 

 be entirely lost, and yet the process of secretion and the 

 evolution of animal heat be still continued for a consider- 

 able time. 



Emily. Hence it seems that impressions made on the 

 nerves, are not transmitted to the brain, and this you 

 considered an important duty of the nervous power. 



Dr. B. We have jno right to say that the nerves do 

 not, in such cases, transmit the impressions which they 

 receive, because if we irritate them, we see that the rnus- 



