130 THE BIOLOGICAL PROBLEM OF TO-DAY 



growth of certain parts of the body, and a lesser 

 growth of other parts. Workers' food stimulates 

 growth in the jaws and brain, retards growth in 

 the wings and sexual cells. Queens' food has the 

 opposite action.' There is a correlation between 

 retardation of the sexual glands and acceleration 

 of the development of the head, just as in verte- 

 brates there is a correlation between the sexual 

 glands and the secondary sexual characters. ' The 

 characters by which the workers differ from the 

 queens, therefore, are not innate, but are produced 

 secondarily/ 



Quite independently, but simultaneously, Herbert 

 Spencer has suggested the same explanation as 

 Emery. Moreover, he has used the conditions that 

 exist among the state-forming insects as a strong 

 argument against Weismann's doctrine of deter- 

 minants. The observations of many careful persons, 

 such as Charles Darwin, Emery, and others, show 

 that in many species of ants the extreme types of 

 individuals are connected by many intermediate 

 forms. (Apud Emery, this is the case in many 

 Myrmicidce, in most Oamponotidce, and in Azteca.) 

 These forms are transitional, not only in general 

 size, but in the degree to which the genital organs 

 have been arrested, and in the peculiarities of 

 the jaws. 



Spencer explains these transitional forms, and I 

 agree with him, by supposing that the stoppage in 

 food supply has taken place at different times after 

 development has begun. ('It must happen that 

 the stoppage of feeding will be indefinite/) Thus, 



