220 ANIMAL AUTOMATISM. [LECT. 



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 

 uninjured 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 



