298 POPULAR SCIENCE MONTHLY 



species. On such assumptions it is, of course, impossible to under- 

 stand how the workers can have come by the obviously adaptive and 

 exquisitely correlated characters, which they are unable to transmit. 

 It will be remembered that neo-Darwinians and neo-Lamarckians, in 

 the persons of Weismann and Herbert Spencer, locked horns over this 

 matter some years ago. Both in this and in many similar discussions, 

 the very premises which both parties accepted are unwarranted. In 

 the first place, it is now known that workers readily become fertile 

 when well fed and that they can and often do produce normal young 

 from unfecundated eggs. Although these young are usually, if not 

 always, males, it is evident that these males, through the eggs which 

 they fertilize, can transmit the characters of their worker mothers to 

 succeeding generations of queens and workers. Thus the congenital, 

 and perhaps even the acquired, characters of the worker are not neces- 

 sarily lost, but can be gathered up into the germ-plasma of the species. 

 In the second place, most, if not all of the characters of the worker 

 are not qualitatively but only quantitatively different from those of the 

 queen. In other words, the worker does not differ from the queen as 

 a mutant, but as a fluctuating variation, which has been produced by 

 imperfect or irregular feeding during its larval stages. This is true 

 alike of morphological, physiological and psychological characters. 

 Even when the queen fails to manifest the worker instincts, we are not 

 justified in doubting her ability to do so under the proper conditions. 



The hitherto unsuspected capacity of the queen ant is beautifully 

 illustrated by another set of facts, which at the same time show the 

 close connection between adaptive behavior and regulation, or regen- 

 eration. Under normal conditions the queen, after rearing a brood 

 of workers, no longer takes part in the ' muck and muddle of child- 

 raising ' but seems to be as indifferent to the young of her species as 

 some women who have brought up large families. If, however, the 

 firstling brood of workers be removed and the queen isolated, she forth- 

 with begins to bring up another brood, precisely as in the first instance, 

 provided her body still contains sufficient food-tissue. She thus re- 

 generates the lost part of her colony, just as a mutilated earthworm 

 regenerates its lost segments. In the ant the absence of workers acts as 

 a stimulus to restore the colony, just as the absence of segments leads 

 the earthworm to complete its body. 



The regulatory activities of the queen ant are, of course, highly 

 adaptive and hence evidence of the variability which is so clearly mani- 

 fested in the physical structure of these insects. There is no con- 

 tradiction in the coexistence of such variability with the very stable 

 character of certain instincts like those to which I have called attention, 

 for an organism may be extremely plastic in some of its activities and 

 rigidly conservative in others. It is evident that the remarkable vari- 



