BY DR. MICHAEL FOSTER. 41 1 



If a morsel of paper were now placed on the surface of the 

 right thigh, the right foot would be brought up to rub away 

 the paper, the left foot remaining quiet. Hold tight the right 

 foot, or better still, place a ligature below the right knee, and 

 cut away the whole lower leg and foot. If the acid paper be 

 now placed on the right thigh, convulsive twitching of the 

 stump (ineffectual as far as the removal of the paper is con- 

 cerned) will follow, and then the left foot will be brought 

 across to rub the paper away. 



In both these cases we have instances of an apparent power 

 of the organism, even in the total absence of the brain, to 

 change its customary proceeding and to adapt itself at once 

 to new circumstances, instances which have led some to speak 

 of a conscious intelligence residing in the spinal cord. 



Obs. X. As an instance tending directly to the contrary 

 supposition, the following experiment may be performed: 



In a shallow glass or porcelain dish, place enough water to 

 reach up to the head of a frog. Line the sides and bottom 

 of the vessel inside with felt or blotting-paper. 



Place an nnmutilated frog in the water, and then gradually 

 raise the temperature. Cover the top of the vessel with a 

 piece of gauze or netting, to prevent the escape of the frog. 



As the temperature rises the frog becomes uneasy, and after 

 20 C or 30 C is reached makes violent attempts to escape. 



Place in exactly similar circumstances a frog whose medulla 

 has been divided ; the water should cover the whole of the 

 animal up to just below the wound in the neck (care being 

 ta*.en that the water gains no access to the spinal cord). 



Up to 30 or above, no movement of any kind is visible. 

 About 35, slight twitch ings may be observed in some of the 

 muscles of the limbs and flanks. At 38-40 the whole body 

 becomes rigid (rigor calorie), and the frog is dead without 

 having made the slightest attempt to escape from the hot 

 water. 



This observation goes quite as far to prove that the frog, in 

 the absence of the brain, has no consciousness or volition as 

 Observation IX. seems to point to the contrary. Both obser- 

 vations are probabl\ T to be explained without any reference, 

 negative or positive, to consciousness or volition. 



^Obs. XI. As a useful exercise, the student may la}* bare the 

 roots of the 7th, 8th, 9th, and 10th spinal nerves as directed 

 in Chap. XXXII., the medulla having previously been divided. 

 Let him now divide the posterior root of say the 7th nerve, 

 and determine on what parts of the skin the acid papers may 

 be placed without producing reflex actions. In this way he 

 may ascertain the distribution in the skin of the sensory fila- 

 ments of that nerve ; and in the same way with the other 

 nerves. 



