INTRODUCTION 9 



f 

 there is very little division of labor. Each man makes his 



own weapons, each knows how to weave coarse cloth, how 

 to cook, how to farm, etc. Savages do not have as good 

 weapons as do people who leave the making of weapons to 

 certain men whose special business it is. What kind of 

 pocketknives or pencils do you think the boys of this 

 country would have if each boy had to make his own 

 pocketknife or pencil ? What kind of scissors and thread 

 would the girls have if each girl had to make them her- 

 self ? Our muscle cells can contract better than the 

 ameba ; the cells in the lungs can absorb oxygen better 

 than the ameba. We have just as great an advantage in 

 digestion, feeling, and other processes ; for the ameba eats 

 without a mouth, digests without a stomach, feels without 

 nerves, breathes without lungs, and moves without muscles. 

 Division of labor between the sexes also occurs among 

 the higher animals. Those who desire that man and 

 woman should have the same education and work would 

 violate the biological law of "progress by specialization," 

 which could only cause race degeneration. 



A part of the body which is somewhat distinct from 

 surrounding parts, and has special work to do, is called an 

 organ ; the special work which the organ does is called its 

 function. The eye is the organ of sight. The skin is an 

 organ ; its function is to protect the body. This book will 

 treat of (1) the structure, appearance, and position of each 

 organ, or anatomy; (2) the function of each organ, or 

 physiology; (3) the conditions of health for each organ, 

 or hygiene ; (4) the conditions under which each organ 

 worked in the primitive life of the race ; (5) the effects of 

 change of environment ; (6) the anatomy of man compared 

 with the lower animals. (5) belongs to the science of 

 Ecology. These sciences are parts of the science of Biology. 



