20 THE POPULAR SCIENCE MONTHLY. 



sit upon her eggs there is a feeling of aversion ; while one which 

 fights in defense of her chickens is admired. 



Egoistic acts, as well as altruistic acts, in animals are classed 

 as good or bad. A squirrel which lays up a store of food for the 

 winter is thought of as doing that which a squirrel ought to do ; 

 and, contrariwise, one which idly makes no provision and dies of 

 starvation, is thought of as properly paying the penalty of im- 

 providence. A dog which surrenders its bone to another without 

 a struggle, and runs away, we call a coward — a word of repro- 

 bation. 



Thus then it is clear that acts which are conducive to preser- 

 vation of offspring or of the individual we consider as good rela- 

 tively to the species, and conversely. 



The two classes of cases of altruistic and egoistic acts of ani- 

 mals just given, exemplify the two cardinal and opposed principles 

 of animal-ethics. 



During immaturity benefits received must be inversely propor- 

 tionate to capacities possessed. Within the family-group most 

 must be given where least is deserved, if desert is measured by 

 worth. Contrariwise, after maturity is reached, benefits must 

 vary directly as worth : worth being measured by fitness to the 

 conditions of existence. The ill fitted must suffer the evils of un- 

 fitness, and the well fitted profit by their fitness. 



These are the two laws which a species must conform to if it 

 is to be preserved. Limiting the proposition to the higher types 

 (for in the lower types, parents give to offspring no other aid than 

 that of laying up a small amount of nutriment with the germ ; 

 the result being that an enormous mortality has to be balanced by 

 an enormous fertility) — thus limiting the proposition, I say, it is 

 clear that if, among the young, benefit were proportioned to effi- 

 ciency, the species would disappear forthwith ; and if, among 

 adults, benefit were proportioned to inefficiency, the species would 

 disappear by decay in a few generations (see Principles of Soci- 

 ology, section 322). 



What is the ethical aspect of these principles ? In the first 

 place, animal life of all but the lowest kinds has been maintained 

 by virtue of them. Excluding the Protozoa, among which their 

 operation is scarcely discernible, we see that without gratis bene- 

 fits to offspring, and earned benefits to adults, life could not have 

 continued. 



In the second place, by virtue of them life has gradually 

 evolved into higher forms. By care of offspring which has be- 

 come greater with advancing organization, and by survival of the 

 fittest in the competition among adults which has become keener 



