morphosis of the females into workers among state-forming insects give an important support to the view that the germ-plasm is actually composed of ids, and these again of primary constituents of the different independently varying parts of the body—that is of 'determinants.' It is necessary to suppose that at first only small groups of determinants varied: in the case of ants possibly those of the reproductive organs and wings, and at the same time, many of those of the brain. New determinants arose as the old ones disappeared; and as thus more and more numerous and comprehensive groups of determinants gradually underwent increased modification, a 'worker-id' finally arose. In like manner other 'female' ids were converted into 'queen-ids'; and among the ants possessing soldiers, part of the 'worker-ids' became differentiated to form 'soldier-ids.'
I cannot help thinking that the otherwise unexplained phenomena of polymorphism become clear and comprehensible,—both as actual phenomena and in their phyletic development,—if we accept the view that the germ-plasm is composed of ids—a view founded on facts of a very different kind. And it is not necessary to make any new assumptions special to this instance, for everything takes place exactly as I have supposed to be the case in all processes of transmutation. I concluded from the phenomena of heredity that at the beginning of a metamorphosis there is in all cases a variation of the determinants of those parts which have to adapt themselves to new demands of the conditions of life. But even these primary variations do not necessarily depend
