ANTIQUITY OF MAN'S BODY-BUILDING INSTINCTS. 



By L. C. WoosTER, Ph. D., Emporia. 



T IFE reaches so far back into the dim recesses of the earth's 

 ^-^ history that the geologist alone is competent to make 

 even an estimate of its antiquity. Furthermore, the geologist 

 is aware that his estimates of the lengths of geological times 

 are merely approximations to the true periods; still, these 

 eras of time are so vast that it is beyond question entirely safe 

 to use these estimates for most scientific purposes. Averaging 

 the opinions of several leading geologists, we may give the 

 lengths of the eras as follows : 



Archean 10+ million years. 



Proterozoic 171 



Cambrian 6 



Ordovician 6 



Silurian £2 



Devonian 3J 



Carbonic 4| 



Jura-Trias 31 



Cretaceous 31 



Tertiary 2 



Quaternary 1 



Total 60+ million years. 



Before giving the times of appearance of the several body- 

 building instincts, it will be necessary to discuss briefly the 

 signification of this new term in biology. 



An instinct has been defined as a propensity of each indi- 

 vidual to do those things which reason afterwards pronounces 

 to be good, and which were done prior to experience and inde- 

 pendent of instruction. 



Professor James says that an instinct is usually defined as 

 the faculty of acting in such a way as to produce certain ends, 

 without foresight of the ends, and without previous education 

 in the performance. (Psychology, Brief Course, page 391.) 

 Professor James further says that instincts are functional 

 correlatives of structure, and that with the presence of a cer- 

 tain organ goes almost always a native aptitude for its use. 

 This organ is used in response to a certain stimulus, says 

 Professor James, and this stimulus may be a sensation, as 



(121) 



