HYPNOTISM IN ANIMALS. 77 



uralist, Herr Geupel-White, has most kindly placed at our disposal the 

 rich material his zoological garden affords, to assist us in these experi- 

 ments. 



My former experiment with the swan was also performed in Herr 

 Geupel-White' s garden. In the experiments with the small birds, the 

 condition of immobility, which can change to actual sleep, is only 

 caused by the effect of the impression made in the animals, through 

 touching the skin and overpowering the resisting muscles. You will 

 see this in the continuation of our experiment. That, however, the ex- 

 citing of certain cutaneous nerves alone changes the normal functional 

 capacities, and calls forth a singular state of stupidity, is proved by 

 the following highly-interesting experiment with a frog, which Dr. 

 Lewissohn, in Berlin, has suggested, and most thoroughly investigated : 



If one places a frog on its back, it does not remain in this unnatural 

 position for an instant, but, on the contrary, turns itself over and 

 escapes. This you may see yourselves, when I endeavor to place this 

 frog on its back. But please notice the astonishing result if we tie its 

 two fore-legs with a string. (The lecturer tied threads around each 

 of the frog's fore-legs, drew the threads tightly, and laid the animal, 

 as before, on its back.) You see that the frog, breathing heavily but 

 otherwise quite motionless, now lies on its back, and does not make 

 the slightest attempt to escape, even when I endeavor to move it. It is 

 as though its small amount of reasoning power had been charmed 

 away, or else that it slept with open eyes ; an analogous condition to 

 that which we saw in the crabs, hens, and little birds. The only dif- 

 ference is, that the actual connection of the phenomena is much clearer. 

 Now, I press upon the cutaneous nerves of the frog, while I loosen 

 and remove the threads on the fore-legs. Still the animal remains 

 motionless upon its back, in consequence of some remaining after-effect ; 

 at last, however, it returns to itself, turns over, and quickly escapes. 



That it is here a matter of restraint upon the nervous centres, in 

 consequence of the pressure on the sensitive cutaneous nerves, Lewis- 

 sohn has already proved. In this experiment, the impulse of motion 

 on the nervous fibres, which proceeds from the so-called motory centre 

 of the brain and spinal cord, remains quite capable of action on one 

 side, while, as regards the other side, the remarkable condition of stu- 

 pidity will no longer happen, if we have divided the cutaneous nerves 

 before tightening the threads. 



Sometimes it is possible to make the frog lie motionless on its back 

 without the threads ; but this proves nothing against the soundness 

 of Dr. Lewissohn's results. 



But let us return to our old experimentum mirabile 1 of the hen. 

 According to the analogy of the last experiments with the frog, the 

 tying together of the hen's feet, although not necessary, may con- 

 tribute something to the effect in Kircher's experiment, not only by 



1 Admirable experiment. 



