380 THE WORLD OF LIFE 



and must therefore be proportionate in each species to its 

 needs, not beyond those needs. In the lowest animals, whose 

 numbers are enormous, whose powers of increase are 

 excessive, whose individual lives are measured by hours or 

 days, and which exist to be devoured, pain would be almost 

 or quite useless, and would therefore not exist. Only as the 

 organism increased in complexity, in duration of life, and in 

 exposure to danger which might possibly lead to its death 

 before it could either leave offspring or serve as food to some 

 higher form — only then could pain have any use or meaning. 



I have now endeavoured, very roughly, to follow out this 

 principle to its logical results, which are, that only in the 

 higher and larger members of the highest vertebrates — 

 mammals and birds, do the conditions exist which render 

 acute sensations of pain necessary, or even serviceable. 

 Only in the most highly organised, such as dogs and horses, 

 cattle, antelopes, and deer, does there appear to be any need 

 for acute sensations of pain, and these are almost certainly, 

 for reasons already given, very much less than ours. The 

 logical conclusion is, therefore, that they only suffer a very 

 moderate amount of pain from such bodily injuries as they 

 are subject to in a state of nature. 



I have already shown that in most cases, even from our 

 much higher standard, their death would be rapid and 

 almost painless ; whence it follows, that the widespread idea 

 of the cruelty of nature is almost wholly imaginary. It 

 rests on the false assumption that the sensations of the 

 lower animals are necessarily equal to our own, and takes 

 no account whatever of these fundamental principles of 

 evolution which almost all the critics profess to accept. 



There is, of course, a large body of facts which indicate 

 that whole classes of animals, though very highly organised, 

 suffer nothing which can be called pain, as in the insects ; 

 and similar facts show us that even the highest warm-blooded 

 animals suffer very much less than we do. But my argu- 

 ment here does not depend upon any such evidence, but 

 on the universally accepted doctrine of evolution through 

 adaptation. According to that theory, it is only life-preserv- 

 ing variations, qualities, or faculties that have survival value : 

 pain is one of the most important of these for us, but it is 



