50 Instinct and Intelligence 



on by a diffused nervous force, is impelled to 

 wander first here and then to another spot, in 

 place of taking a decisive instinctive action. 



From these experiments we learn that the 

 definite co-ordinate action of the different parts 

 of a Medusoid's body takes place through 

 means of its nervous system. 



The ordinary swimming movements of a 

 Medusoid depend on the regularly recurring 

 contraction and relaxation of the muscular 

 fibres of the bell and velum. This action in 

 its turn depends on a constant flow of energy 

 from its surroundings to the sense-organs, and 

 from thence to the nervous and muscular 

 systems, which are charged with potential force 

 derived from metabolic processes carried on by 

 their living protoplasm. A discharge of energy 

 from a series of nerve cells having thus been 

 released, their living matter for the instant is 

 exhausted, and until it receives a fresh supply 

 of energy derived from metabolic processes 

 it cannot act on the muscular fibres. During 

 the instant, therefore, that the supply of 

 potential energy is being renewed, the kinetic 

 energy received from the sense-organs is sus- 



