1884.] on the Fhjsiological Aspect of Mesmerism. 31 



bility, the decrease in reaction being earliest distinct in the centres of 

 special sense. When it is in this state, it may be propped up against 

 a support with its legs crossed under it, or placed so that it rests on 

 its head, or placed on its side with its legs arranged in this or that 

 fashion, without offering the least resistance. Strong stimuli, or 

 certain apparently lesser ones, for example a dash of water, cause it 

 to recover its position slowly ; it then usually sits for several minutes 

 motionless, and only after some time regains its normal sensitiveness 

 and activity. I show you here a frog in the early hypnotic state. 



I have spoken of the frog as being hypnotised or mesmerised. 

 Let us consider what is meant by this. I think it is obvious that the 

 animal does not remain passive from any astuteness on its part ; it is 

 incredible that the frog, finding its efforts to escape ineffective, should 

 make up its mind to remain quiet, and should, although at liberty to 

 move, stay still for hours, becoming more and more determined as 

 time goes on to take no notice of noises, of flashes of light, and of 

 pinching of its skin. On the contrary, it is, I think, obvious that in 

 some way its will has become paralysed. In order to attempt to 

 explain how this is brought about, we must consider another aspect 

 of reflex action, an aspect which is very little understood. 



You remember that a brainless frog will, when its leg is gently 

 pinched, kick out the leg ; but if just previously some other part of the 

 body has also been pinched, one of two opposite things may take place : 

 the leg may be kicked out more quickly and vigorously, or it may not 

 be kicked out at all. In both cases the nerve centre involved in pro- 

 ducing the movement of the leg receives an additional impulse from 

 another nerve centre, but in one case the additional impulse increases 

 the activity of the nerve centre involved in the reflex action, in the 

 other case it annuls this activity — there is, to use the physiological 

 term, an inhibition of the " reflex " nerve centre. 



To take another instance, a frog without its cerebral hemispheres, 

 but with the rest of its nervous system, will croak when its sides are 

 gently touched ; but if at the moment of touching it, its leg be 

 pinched, it moves or jumps, but does not croak. Here the motor 

 centre which causes the movements of the muscles in croaking, receives 

 nervous impulses from two sensory centres ; one of these being set in 

 activity by touching the sides of the frog, the other from pinching its 

 leg. The impulses from the former tend to make the motor centre 

 active, and so produce a croak ; but the exciting effect of these 

 impulses is annulled by the impulses coming from the latter centre ; 

 in other words the nerve centre involved in croaking is inhibited. 

 Inhibition by impulses proceeding from the cortex of the brain occurs 

 every day of our lives. The " will " is perpetually being brought 

 into play to inhibit some nerve centre or other. For example, you 

 may be on the verge of yawning, when it suddenly occurs to you that 

 it will be better not to do so ; you suppress the yawn without moving 

 a muscle. What happens is this. An inhibitory nerve impulse is 

 sent from the cortex, and puts a stop to the indiscreet activity of a 



