242 THE POPULAR SCIENCE MONTHLY 



THE MAKING OF THE SCIENTIFIC INVESTIGATOR 



By THOMAS H. MONTGOMERY, Jr. 



PROFESSOR OF ZOOLOGY, UNIVERSITY OF PENNSYLVANIA 



f I THE question is old but important, how far a man may influence 

 -*- his destiny and career by power of will and by training. Very 

 often it is argued that his future lies entirely with himself, that he is 

 modeling clay in his own hands. From this comes the expression of 

 " the self-made man." Yet " there's a divinity that shapes our ends, 

 rough hew them how we will," a might that the biologist calls inherit- 

 ance. For by no manner of endeavor can a man make himself a bird 

 or fish, nor can he divorce his mind from his body. An organism may 

 be introduced to new conditions of life, by volition or by circumstance, 

 and though it may change to some extent, it can not become entirely 

 different from what it was at the start and still continue to live. As the 

 twig is bent the tree inclines, that is, bends off from the normal path, 

 but it does not become another kind of tree. The gardener can change 

 the growth of a flower by placing certain solutions in the soil, but he 

 simply adds another substance to it; or the experimenter can prevent a 

 skeleton from developing by withdrawing from the medium certain 

 salts, but he has only subtracted a certain substance. Some qualities 

 may receive an added impulse, others may be retarded, monsters may 

 be engendered, but no man has yet changed one being into a very dif- 

 ferent one. 



Thus there are genetically diverse kinds of beings, and this is as 

 true for men as for the rest of creation. What will be the outcome of 

 any individual is to greatest extent a matter of his inheritance, it is 

 blood that tells. All of us make our advent naked and helpless, all 

 seemingly equally dependent upon the maternal care, all have to learn 

 by experience. Yet no two human infants are alike, except to the inex- 

 perienced eyes of an old bachelor, for because they are of different 

 parentage they possess at the beginning different qualities, and it is 

 probable that infants arc as unlike as full-grown men and women, 

 though in not the same ways. Indeed, every step in our growth has been 

 conditioned by our ancestry. For the organism is much more than a set 

 of substances and structures, it is a chain of processes linked continu- 

 ously with the remote past and the outcome depends very largely upon 

 the initial condition. This is the cardinal point that educators have 

 grasped only recently, and about which some of them are still strangely 

 in doubt. A man can not mold himself entirely, nor can his teachers 

 wholly change him, for he is largely fashioned by his inheritance. 



But though inheritance handles the reins, the course of life depends 



