SUMMARY 373 



injury. In each case, the reactions of the individual 

 as a whole are correspondingly limited. 



The Muscles: If the function of the muscles is lost 

 or hindered, the reactions of the individual may be 

 as greatly affected as by depression of the function of 

 the brain. If the muscles are disconnected from the 

 brain by severing the connecting nerves, or if the func- 

 tion of the muscles is suspended by curare, the in- 

 dividual will be as helpless as if his brain had been 

 removed. For a time, his life may be prolonged by 

 artificial respiration ; but he can move no muscles ; 

 he can produce only a negligible amount of heat ; he is 

 powerless, dumb and cold little better than dead. We 

 see, therefore, that the muscles bear just as mechanistic 

 a relation to the work of the individual as a whole, as 

 the motor of an automobile bears to the reactions of 

 the whole machine. 



The Adrenals: Excision of the adrenals causes a 

 progressive decline in muscular power and in the pro- 

 duction of heat until death, which inevitably occurs 

 within a few hours. The H-ion concentration of the 

 blood increases progressively with the approach of 

 death. 



The Thyroid: The excision of the thyroid in carniv- 

 ora and in man causes a rapid diminution of muscular 

 power and a diminution in the production of heat. 

 Sexual desire and procreation are depressed or lost ; the 

 mind is weak ; the individual becomes large, flabby and 

 stupid a repulsive human caricature. Feeding thy- 

 roid extract to such an individual transforms him into 

 a comparatively normal physical and mental being 

 a markedly mechanistic phenomenon. 



