108 CALIFORNIA ACADEMY OF SCIENCES. 



pass muster in such a struggle for existence of individ- 

 ual with individual; or how could any altruistic trait be 

 evolved? Mr. Romanes, it seems, has not adequately 

 shown this. The parental instinct does not constitute a 

 strictly corresponding instance, for the survival of the 

 fittest must of course mean the survival of those indi- 

 viduals best fitted to leave offspring. In the case of the 

 dry goods merchant just referred to, he would only be 

 the fittest individual to survive in the long run, if he 

 were able not merely to win his place among his com- 

 petitors, but to maintain it through his heirs. Repro- 

 duction is merely growth beyond the individual, and 

 accordingly the longer the line of potential descendants 

 which an individual leaves, the longer will that indi- 

 vidual survive, speaking broadly. Consequently, no 

 sexual individual is really complete. It can only be- 

 come complete by perpetuating itself, which demands a 

 mate. 



In this view of reproduction a clue may be found to 

 the introduction of altruistic traits. Every individual's 

 bodily immortality is conditioned by the existence and 

 well being of some other individual. The survival of 

 the individual is thus clearly wrapped up with the sur- 

 vival of the family, and natural selection would there- 

 fore encourage any tendency which would promote the 

 family, even to the disadvantage of certain members of 

 it. Thus the habit of feigning lameness by some birds 

 to lure an enemy from the young, is a source of danger 

 to the parent but a protection to the young. If in any 

 case, however, the danger to the parent were greater 

 than the protection to the young, the habit could not 

 have been acquired, for whenever the parent were lost 

 through the exercise of this altruistic habit, the young 

 would in the great majority of cases die of neglect, and 

 the habit would not become established. 



