INTRODUCTION 7 



the boy's individual (ontogenetic) experience, but is 

 the result of the adaptation of his progenitors, through 

 natural selection, throughout the vast eons required 

 to evolve the species, during which the frequent re- 

 currence of similar mechanical injuries resulted in the 

 implantation of a neuro-muscular mechanism, adapted 

 to discharge automatically, at the needed moment, 

 the required amount of energy in the form of an adap- 

 tive muscular action. 



It seems probable that in like manner most, if not 

 all reactions are performed. Every adequate stimulus 

 awakens an ontogenetic or phylogenetic memory or 

 association. This leads to adaptive energy transforma- 

 tion an act performed. The energy thus expended 

 is subtracted from the sum total of available potential 

 energy stored in the body. If these stimuli be of suffi- 

 cient intensity and sufficiently prolonged, the stores of 

 potential energy are diminished, and acute acidosis is 

 established, i.e., the state of shock may be produced. 

 But the discharges may be of such slight intensity and 

 of such short duration that no appreciable diminution 

 in potential energy is caused ; in which case the re- 

 sponses as in the case of the boy stepping on a 

 stone are deemed normal and not pathologic. 



Our experiments have demonstrated that traumatic 

 and psychic stimuli produce an increased hydrogen-ion 

 concentration of the blood, i.e., increased acidity. If 

 the acid production exceeds the body's capacity for 

 neutralization, there results a condition of acute acid- 

 ity to which may be due in part, or perhaps entirely, 

 the rapid respiration, the sweating, the thirst, the rest- 

 lessness, which are present in shock. 



