8o2 THE POPULAR SCIENCE MONTHLY. 



of the lower animals when mesmerized : in these the phenomena, as 

 far as at present observed, are much simpler than they are in man. If 

 a frog be turned over on its back, it at once regains its normal posi- 

 tion ; if, however, it be prevented from doing so, and its struggles are 

 for a short time gently suppressed, it becomes hypnotized. Then, 

 although it be left at liberty to regain its normal position, it will not 

 attempt to do so. Apart from the movements it makes in breathing, 

 it lies motionless. If it has been held for a short time only, the hyp- 

 notic state does not last long, usually from one to five or ten minutes ; 

 but, if the movements it makes, say, at the end of one minute, or of 

 five minutes, and so on, are suppressed, it will not infrequently happen 

 that the frog will then stay without further movement for a consider- 

 able time, sometimes even for many hours. During the first part of 

 this time a slight pinch, a sudden flash of light, or a loud noise, will 

 usually cause it to turn over and sit up in its normal manner. For a 

 moment or two it looks a little dull and confused, but rapidly regains 

 its normal activity. During the latter part of this time it responds 

 less and less to external stimuli. 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. 



I have spoken of the frog as being hypnotized or mesmerized. Let 

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

 mal does not remain passive from any astuteness on its part ; it is in- 

 credible 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 pinch- 

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

 way its will has become paralyzed. In order to attempt to explain 

 how this is brought about, we must consider an aspect of reflex action 

 which is very little understood. 



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-center involved in producing the move- 

 ment of the leg receives an additional impulse from another nerve- 

 center, but in one case the additional impulse increases the activity of 

 the nerve -center involved in the reflex action, in the other case it 

 annuls this activity — there is, to use the physiological term, an inhibi- 

 tion of the " reflex " nerve-center. 



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-center or other. For example, you 

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



