It is not increased by an elimination which merely changes the character of defects without reducing their amount. Vices are the negative of will power: criminal traits are the negative of development. They are not independent characters corresponding to changes in the germ cell.
The main result of the preceding discussion is to show that the unit-characters of the germ-cell do not correspond to the moral and immoral traits made emphatic in social science. The biologic characters important in social science are few in number, of which will power is the only one on which the present progress of the race depends. Social traits correspond to the peculiar conditions in which society finds itself and they grow in number as the complexity of the environment increases. Chastity, thrift or temperance indicates desirable social conditions which are pictured in the ideal they create. There could be forty such characters with no biologic change except a growth of will power. Progress in man is due to concentration of energy. The central organs, the brain and its adjuncts, have grown at the expense of the terminal organs such as the hand, foot, teeth and jaw. More energy goes to the brain and less to the external structures of vital importance to lower animals. This concentration of energy results in the prolongation of childhood, the growth of psychic powers and the dominance of will over instinct. But at the same time it creates a deficit in terminal organs which forces them into a state of decay. The marks of these changes are the psychic effects revealed in thought and the regressive effects seen in terminal organs. A single biologic tendency could thus create all the difference that separates man from other animals.
We are now in a position to discuss the variations that create differences between parent and child. One source of difference is degeneration, caused by a surplus of nutriment. This clogs the system, produces morbidness and creates auto-intoxication. The final mark is a weak will. The lack of central control is prominent in degeneration and leads to many manifestations of which hysteria is an example. A second difference of parent and child is due to retardation. Each organism in its development repeats the history of its ancestors. An imperfect recapitulation means that the growth of the child stops short of the development of the normal ancestor. From this source many variations arise. A third difference between parent and child is caused by regression. As distinguished from degeneration and retardation, regression is only partial indicating real progression in unobserved parts. In man the terminal organs fail to come up to the standard set by earlier development. The central organs, however, are progressive and their growth is the real cause of the regression of terminal organs.