January 10, 1913] 



SCIENCE 



47 



to maturity; the other found the germ 

 simple and homogeneous, but required some 

 unknown force, some spiritiis rector or vis 

 essentialis, to cause the homogeneous to 

 become heterogeneous. The one placed all 

 emphasis upon the germ, the other upon 

 outside forces or conditions. 



Modern students of development recog- 

 nize that neither of these extreme views is 

 true — adult parts are not present in the 

 germ, nor is the latter homogeneous — but 

 for more than a hundred years opinions 

 have been vibrating in the field between 

 these two extremes. 



Students of development, whether it be 

 that of the individual or of the race, are 

 like those ancient mariners who sailed that 

 dreaded strait on the one side of which 

 frowned Scylla and on the other roared 

 Charybdis — in shunning the Scylla of pre- 

 formation they run into the Charybdis of 

 epigenesis, in avoiding the rocks of prede- 

 termination they fall into the whirlpools of 

 no-determination, in avoiding the perils of 

 fatalism they encounter the dangers of 

 chaotic freedom — while the narrow channel 

 of truth runs somewhere between these two 

 extremes. They tack from one side to the 

 other, ever advancing, ever leaving old 

 dangers behind, ever meeting new ones — 

 and so the science of development zig-zags 

 on. 



At present there can be no doubt that 

 we are sailing nearer the preformation 

 coast than at any time since the modern 

 study of development began under von 

 Baer. In the study of heredity great 

 emphasis is placed, and necessarily so, 

 upon the complexity of the germ and the 

 intrinsic factors of development. There 

 can be no doubt that the main character- 

 istics of every living thing are unalterably 

 fixed by heredity. Men differ from horses 

 or turnips because of their inheritance. 

 Our anatomical, physiological and psycho- 



logical possibilities are predetermined in 

 the germ cells. Whatever the ultimate re- 

 lations of mind and body may be, there can 

 be no reasonable doubt that both have 

 developed together from the germ and that 

 the laws of inheritance apply to one as 

 certainly as to the other. The main char- 

 acteristics of our personalities are born 

 with us and can not be changed except 

 within relatively narrow limits. "The 

 leopard can not change his spots nor the 

 Ethiopian his skin," and "though thou 

 shouldst bray a fool in a mortar with a 

 pestle yet will not his foolishness depart 

 from him." Race, sex, character are pre- 

 determined in the germ cells, perhaps in 

 the chromosomes, and all the possibilities 

 of our lives are there fixed, for who by 

 taking thought can add one chromosome, 

 or even one determiner, to his organiza- 

 tion? 



These modern theories of hei'edity are 

 profoundly influencing human thought in 

 many fields. "We formerly heard that all 

 men were created free and equal; we now 

 learn that all men are created bound and 

 unequal. We were once taught that vol- 

 untary acts, if oft repeated, become habits, 

 and that habits determine character; we 

 now learn that acts, habits and character 

 were foreordained from the foundation of 

 the family. We once thought that men 

 were free to do right or wrong, and that 

 they were responsible for their deeds; now 

 we learn that our reactions are predeter- 

 mined by heredity and that we can no more 

 control them than we can control our heart 

 beats. For ages men have believed in the 

 influence of example, in the uplift of high 

 ideals, in the power of an absorbing pur- 

 pose; for ages men have lived and died 

 for what they believed to be duty and 

 truth, and have received the homage of 

 mankind; or they have lived malevolent 

 and criminal lives and have been despised 



