86 PHYSICAL EXPRESSION. 



cular fibres. The muscle is the index of the nerve- 

 current ; the muscular contraction is the expression 

 of the motor action of the brain, indicating the 

 time, frequency, duration of the nerve-current 

 produced by the central organ. 



If the central nerve-system is the organ gene- 

 rating the force, and stimulating the muscles to 



Fig. 4. Upper Surface of the Hemispheres of the Monkey. The circles and 

 included numerals arc explained in the text (Ferrier). 



contract, can different portions of that mass act 

 separately ? Do certain parts of the nerve- 

 mechanism stimulate special movements ? Are 

 certain movements indications of the activity of 

 certain parts of the central nerve-mechanism ? 



Dr. Ferrier experimented upon the brains of dogs 

 and monkeys with the following results : 



