FORCED MOVEMENTS 157 



facts of comparative physiology do not favour this con- 

 ception. Spontaneous progressive movements exist 

 in Infusoria which possess no nervous system, and even 

 in plant organisms, for example, in the swarmspores 

 of algae. It is an important principle of physiological 

 epistemology that a phenomenon which occurs gener- 

 ally, cannot possibly be the specific function of an 

 organ which is peculiar to a few forms only. Steiner 

 soon found a fact that showed the erroneousness of 

 his theory, the fact that the decapitated shark con- 

 tinues to swim about in the tank. Schrader had like- 

 wise found that the frog without a brain is still able to 

 perform spontaneous progressive movements. Steiner 

 maintains further that " the brain is defined by the 

 general centre of movement in connection with the 

 action of at least one of the higher sensory nerves." 

 "In addition to its great simplicity this definition has 

 still another advantage, namely, that it is satisfied by a 

 single experiment ; because of the two elements of 

 which the definition is made up, one element is always 

 given anatomically. This is the higher sensory nerve, 

 whose presence also vouches for its function. The 

 one experiment that it is necessary to make has to 

 prove that in addition to the sensory apparatus the gen- 

 eral centre of movement also exists. The proof is then 

 complete if the one-sided removal of the central nerv- 

 ous part so changes the direction of the movements 

 of the animals that a circus-motion, which is generally 

 known by the name forced movement, takes the place 

 of a forward movement" (Steiner). This idea is 



