Evolution of the Mechanic Arts. 193 



Compelled, because of his weak and relatively helpless 

 generic condition, not only to take to the woods, but to the 

 trees, and to find means of protection and defense outside 

 of himself and his own natural powers, man and his primor- 

 dial types, by the very necessities of arboreal life, devel- 

 oped not only the liands, but the arms, with their co-ordi- 

 dinated capacities of flexure and rigid fixture in an infinite 

 variety of positions, the chest, the bony frame, the back, 

 leg, and other muscles and parts, in which largely reside 

 the mechanical capacities of man and his other adaptations 

 to societary life. It was the continual grasping of the 

 limbs of trees, doubtless, that gave to the hand its opposing 

 thumb, whereby man is able to securely hold the club, the 

 hammer, the spear, the lever, and also the scepter of the 

 world, of which these others are each the analogue and 

 prototype. 



The same necessities furnished man's primordial types 

 with thumbs on the feet as well, which still appear in one 

 stage of human embryological life, but disappear before 

 birth. Under the influence of changed conditions resulting 

 from the abandonment of his perch in the trees for terra 

 firma, man, standing and walking erect, has discarded the 

 thumbed foot, and thereby co-ordinately increased his equip- 

 ment for the various motions required for the performance 

 of mechanical functions, and for making and managing im- 

 plements, tools and machinery. 



Long before our ancestors had abandoned the trees, they 

 had learned to use clubs, stones and other missiles, with 

 the same hands and structures that enabled them to swing 

 from branch to branch and carry on all the operations of 

 arboreal life. From the use of clubs, spears, arrows and 

 other sharp-pointed sticks, in war and in the chase, to the 

 use of sticks as levers, wedges and cutting-tools of all sorts 

 and kinds, for the purpose of upturning stones in their 

 search for snails and other food, for digging up roots, open- 

 ing shell-fish, preparing their weapons, building their places 

 of abode, etc., etc., the progress was regular, and evidently 

 systematic, not simply in the external sense, but in the 

 co-ordinate development of brain function and mass, and 

 the beginnings of thought and reason. Indeed, it seems 

 clear that the enlargement of the brain of the human being, 

 which is recognized as having been gradual, must have had 

 its initial impulse and opportunities through what I may 



