ANIMAL AUTOMATISM. 227 



If the spinal cord of a frog is cut across, so as to 

 provide us with a segment separated from the brain, we 

 shall have a subject parallel to the injured man, on 

 which experiments can be made without remorse; as 

 we have a right to conclude that a frog's spinal cord is 

 not likely to be conscious when a man's is not. 



Now the frog behaves just as the man did. The 

 legs are utterly paralysed, so far as voluntary move- 

 ment is concerned ; but they are vigorously drawn up 

 to the body when any irritant is applied to the foot. 

 But let us study our frog a little farther. Touch the 

 skin of the side of the body with a little acetic acid, 

 which gives rise to all the signs of great pain in an un- 

 injured frog. In this case, there can be no pain, because 

 the application is made to a part of the skin supplied 

 with nerves which come off from the cord below the 

 point of section ; nevertheless, the frog lifts up the limb 

 of the same side, and applies the foot to rub off the 

 acetic acid; and, what is still more remarkable, if the 

 limb be held so that the frog cannot use it, it will, by- 

 and-by, move the limb of the other side, turn it across 

 the body, and use it for the same rubbing process. It 

 is impossible that the frog, if it were in its entirety and 

 could reason, should perform actions more purposive 

 than these: and yet we have most complete assurance 

 that, in this case, the frog is not acting from purpose, 

 has no consciousness, and is a mere insensible machine. 



But now suppose that, instead of making a section 

 of the cord in the middle of the body, it had been made 



