CH. LII.] SENSATIONS AND REFLEXES 761 



they are merely areas through which the nervous impulses must pass 

 in order that the corresponding sensations may be developed. 



In any case, we must recognise that from infancy onwards we 

 never have a, pure sensation, that is to say, an experience devoid of 

 meaning and totally dissociated from past experiences an experience 

 only dependent on end-organ, nerve-fibre and sensory centre. Our 

 experiences come to us for the purpose of adjusting ourselves to the 

 outer world ; consequently they possess such meaning as is necessary 

 for that end. It is true that in infancy our states of consciousness 

 are vague ; but they are always related to previous experiences and 

 are motives for action. Thenceforth they gradually become more 

 definite. The various elements which they contain become differen- 

 tiated, recognised, and separated. What was at first homogeneous is 

 later found to consist of heterogeneous parts. . 



Consequently it is incorrect to say, as is so often said, that with 

 growing experience sensations are grouped together so as to give 

 rise to the perception of objects. It is true that from our adult 

 perception of an object, e.g. of an orange, certain sensations of colour, 

 taste, smell, etc., may be analysed and separated. But a moment's 

 reflection will convince us that our perception of the orange has 

 never arisen by the converse synthesis or building together of such 

 sensations. From infancy onwards the world appears to us (however 

 vaguely) as composed of objects. The sensations of which we have 

 presently to treat are the artificial products of the analytical activity 

 of the Ego. 



Eecognising that sensations are not truly immediate experiences, 

 but are very abstract in origin, we may proceed to consider the 

 various characters with which they may be invested. Sensations 

 may differ from one another in modality or in quality. Mod ally 

 different sensations are derived from different senses, qualitatively 

 different sensations from the same sense. Blue and green are 

 qualitatively different sensations ; it is possible to pass by gradual 

 transition from one to the other. Heat and noise are modally 

 different ; such gradual transition is impossible. 



Now every peripheral end-organ is specially destined to respond 

 to a certain form of stimulus. The end-organs of the ear respond to 

 sound waves : those of the eye to light waves ; those of the skin to 

 heat, cold, touch, and pain. That stimulus to which the end-organ 

 is thus fitted to respond, is called its adequate or homologous stimulus. 

 But an end -organ will often respond to other, inadequate, stimuli. 

 For example, when the eyeball is struck, sparks are seen ; when a 

 "cold spot" on the skin is stimulated by a hot point, a cold 

 sensation results ; when an electric current is applied to the papillae 

 of the tongue, sensations of taste arise. 



Hence it has been argued that the modality of a sensation 



