FUNDAMENTAL FACTS 3 



injurious effects of strong light. Another striking 

 characteristic in such reflexes has also been empha- 

 sised. The movements which are produced are so 

 well planned and coordinated that it seems as though 

 some intelligence were at work either in devising or 

 in carrying them out. The fact, however, that a de- 

 capitated frog will brush a drop of acetic acid from 

 its skin, suggests that some other explanation is 

 necessary. A prominent psychologist has maintained 

 that reflexes are to be considered as the mechanical 

 effects of acts of volition of past generations. The 

 ganglion-cell seems the only place where such me- 

 chanical effects could be stored up. It has there- 

 fore been considered the most essential element of 

 the reflex mechanism, the nerve-fibres being regarded, 

 and probably correctly, merely as conductors. 



Both the authors who emphasise the purposeful- 

 ness of the reflex act, and those who see in it only a 

 physical process, have invariably looked upon the 

 ganglion-cell as the principal bearer of the structures 

 for the complex coordinated movements in reflex 

 action. 



I should have been as little inclined as any other 

 physiologist to doubt the correctness of this concep- 

 tion had not the establishment of the identity of the 

 reactions of animals and plants to light proved the 

 untenability of this view and at the same time offered 

 a different conception of reflexes. The flight of 

 the moth into the flame is a typical reflex process. 

 The light stimulates the peripheral sense organs, the 



