232 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



other physiologists had considered as the expression 

 of pain-sensations. I may mention further that when 

 the motions following the stimulation of the semicir- 

 cular canals were first observed they were considered 

 by some authors as the expression of pain-sensations. 



Norman observed that sharks and flounders react 

 in no way against very severe operations, c. g., the 

 laying bare of the semicircular canals, provided that 

 respiration was not interfered with (10). As soon 

 as the water-supply to the mouth was cut off, they 

 made violent motions, which are characteristic for the 

 condition of beginning asphyxiation and which have 

 nothing in common with conscious acts. Sharks and 

 flounders belong to that class of Vertebrates which 

 have practically no associative memory. 



It therefore seems to me that our experience con- 

 cerning the pain-sensations of animals does not con- 

 tradict our view regarding the limits of associative 

 memory or the consciousness of the metaphysicians. 



Of course I do not expect to convince the senti- 

 mentalists and Darwinians. The former will say that 

 their " feeling ' tells them that an earthworm is 

 capable of pain-sensations. My reply to these is 

 that the burden of proof rests upon them. If a per- 

 son maintains that there is a gaseous Vertebrate in 

 the air it is plainly his duty to prove its existence, and 

 not the duty of all the other scientists to disprove it. 

 Otherwise we might be called upon to waste our lives 

 in disproving the statements of any insane person or 

 impostor. The Darwinians will doubt the possibility 



