240 EVOLUTION OF TO-DAY. 



is, moreover, perfectly logical and consistent. The 

 only objection to receiving it is the same that we 

 have seen in other cases. The results are too great 

 for the explanations. It is hardly possible to be- 

 lieve that natural selection acting on only one indi- 

 vidual of the colony, the queen and not upon her 

 directly, but only through her attendants, could 

 have had so great an effect. Individual variations 

 could have here no influence. Indeed, Darwin, who 

 suggested this explanation, probably had no idea 

 that individual differences, or differences in a few 

 workers, could ever have had any effect on the 

 colony, but rather that those queens producing off- 

 spring, a large majority of which showed this ten- 

 dency toward differentiation into castes, would be 

 better fitted for forming colonies than those whose 

 offspring showed no such tendency, or showed it 

 only in a few cases. Here, therefore, Darwin would 

 admit the necessity of assuming that the variations 

 were considerable in amount, and occurred in many 

 individuals simultaneously. Upon any other suppo- 

 sition this explanation is palpably insufficient, for 

 individual variation can mean nothing ; only those 

 occurring in hundreds of animals at once can be of 

 any moment. 



Summary. 



Natural Selection, or the Survival of the Fittest, 

 was the first explanation ever offered to account for 

 the origin of species according to natural laws. It 

 was this explanation, so simple and intelligible, and 

 yet so significant, which caused evolution to obtain 



