8 DARWINISM AND HUMAN LIFE 



The Question How does This work? But close 

 upon the first question What is this ? there rises a 

 second How does this work ? It is equally natural 

 and necessary, and throughout the progressive 

 periods in the history of biology the two questions 

 have never been far apart. They have evolved 

 together especially during the last hundred years, 

 prompting one another to a more and more pene- 

 trating inquisitiveness. The key-word of the one 

 is structure, or organisation ; of the other function, 

 or activity. The creature which our first question 

 killed and picked to pieces has to be put together 

 again and made to work. What does it do ? how 

 does it do it ? how does it go ? how does it keep 

 a-going ? how does it set other creatures like itself 

 a-going ? how long can it go ? how does it cease 

 from going ? In other words, how does the 

 organism feel and move ? how does it grow and 

 multiply ? how does it waste, recover itself, and 

 finally, in most cases, die ? Above all, what 

 is the secret of its activity and of its power of 

 effective response to the order of nature ? These 

 are some of the physiological problems which 

 recall Clerk Maxwell's boyish question " What is 

 the go of this the particular go of this ? " 



The Question Whence is This ? A third question 

 is Whence is this ? and, though it is probably 

 as ancient as the others, the answering of it is 

 distinctly modern. It is really a double question, 

 for we may inquire into the development the 

 becoming of the individual, and we may in- 

 quire into the history of the race to which the 

 individual belongs. We may study the child- 

 animal in its cradle the bee-grub in the comb, 

 the embryo skate in its mermaid's purse, the 



