340 PHYSIOLOGY CHAP. 



active consciousness in the cord, that is, of an uninterrupted 

 sequence of psychical processes and transitional states, as though 

 an internal stimulus were perpetually acting on the central organ. 

 He therefore inclines to attribute to the cord a sort of transitory, 

 discontinuous consciousness, which only surges up in response to 

 stimuli of a certain intensity, and maintains that our complete 

 consciousness, and that which we attribute inductively to the 

 higher animals, is merely the perfect development of this rudi- 

 mentary spinal consciousness. 



" We may, on this view," Foster l writes, " suppose that every 

 nervous action of a certain intensity or character is accompanied 

 by some amount of consciousness, which we may, in a way, 

 compare to the light emitted when a combustion previously giving 

 rise to invisible heat waxes fiercer. We may thus infer that when 

 the brainless frog is stirred by some stimulus to a reflex act, the 

 spinal cord is lit up by a momentary flash of consciousness coming 

 out of darkness and dying away into darkness again ; and we may 

 perhaps further infer that such a passing consciousness is the 

 better developed the larger the portion of the cord involved in the 

 reflex act and the more complex the movement." 



Though direct confirmation of Foster's hypothesis on the 

 nature of the spinal psychical functions is wanting, it appears to 

 us to be logical and generally admissible. Those who take the 

 manifestations of perception and memory as the distinguishing 

 signs of consciousness, and absolutely deny the psychical character 

 of co-ordinated reflexes, do not reflect that the spinal cord is not 

 claimed as the seat of the higher intellectual functions, but only as 

 that of a simple rudimentary intelligence due to the synthesis of a 

 small group of elementary sensations. The approach of a dog on 

 hearing its own name, the return of a hungry animal to the place 

 where it is accustomed to find food, are conscious acts of perception 

 involving a process of memory. Of course nothing of the sort can 

 be observed in a " spinal " animal. According to Goltz' ex- 

 periments, if two frogs, one normal, the other spinal, are placed in 

 water and the vessel is gradually heated, the normal frog makes 

 movements to escape from the water when the temperature rises 

 to 35 C. ; the spinal frog, on the contrary, makes no attempt to 

 avoid the danger, and, provided the rise of temperature be gradual, 

 will let itself be boiled without effort to escape. If, on the other 

 hand, the spinal frog is thrown into water already heated up to 

 35 C. it will at once make lively movements, which must, 

 according to Goltz, be regarded as unconscious reflexes, because 

 they did not appear under the former conditions of experiment. 

 But from our point of view, these facts even if they show that 

 the spinal frog exhibits no sign of perception and memory do 

 not exclude the possibility of its possessing transitory flashes of 



1 Foster, Text-Book of Physiology, 1897, part iii. p. 983. 



