1 8 ZOOLOGY 



not die ; it continues by those germ cells which, re- 

 maining inactive and biding their time, at length 

 come forth to defeat the forces of death. 



Samuel Butler, in his fantastic story "Erewhon" 

 (anagram of "Nowhere"), states that the Erewhonians 

 believed that the soul of man was not immortal, but 

 that the universe was peopled by potentially immortal 

 beings, who need never die unless they were born into 

 the world. These beings, it was held, were aware that 

 death would eventually follow birth, but such was 

 their desire and curiosity to know what it was to be 

 alive, to be actual living people, that they could not 

 resist. They were willing to accept death as the price 

 of that precious experience. This fantasy now turns 

 out to embody a truth, and it is an actual fact that 

 death is the price of the higher life. 



Metabolism j. Cells also build up and break down ; the living 

 cell maintains its identity, yet is constantly in a state 

 of change. Biologists have invented certain terms to 

 use in referring to these activities. The changes going 

 on in the cells, and consequently in the body, are 

 spoken of in general terms as metabolism, with the 

 adjectival form metabolic. Thus we say, the body 

 exhibits metabolism, or the metabolism was intense, 

 or the metabolic processes led to such and such results. 

 This word "metabolism" covers a great many things, 

 and for more exact (though still vague) definition we 

 speak of anabolism, the processes tending to build up 

 the body, and katabolism, the processes connected with 

 tearing it down, expending its energies for the per- 

 formance of work. Roughly, these distinctions are 

 like those between saving and spending. Naturally, 

 one cannot spend without having accumulated, but 

 at any particular time; one or the other process may 



