Page Six 



EVOLUTION 



Febkuary, 1928 



What Can Children Inherit ? 



By Henshaw Ward 



n^HE student of heredity will tell you that no abuse of body 

 •'- or mind can be inherited, and that no good training of body 

 or mind can be inherited. He would go so far as to say that 

 the following imaginary case illustrates the truth: "Take a pair 

 of infants (a boy and a girl) to a wilderness and bring them up 

 without any education of body or mind; take another pair of 

 infants who have inherited the same qualities as the first pair 

 and give them every advantage of good breeding; let each paii 

 mate and produce a son; the son bom in the wilderness will 

 have as much ability as the son born in fortunate surroundings. 



I am not saying that this imaginary case represents the whole 

 truth, nor that all biologists are agreed as to what the truth is. 

 I am just giving an example to show picturesquely the two 

 elements of life that biologists dispute about — (1) the germ-cell 

 by which qualities are transmitted to children; (2) the bodily 

 and mental changes produced in a person after he is born. 

 All the influences that act upon a person (such as climate, food, 

 training, accidents) are called the "environment." The effects 

 of the environment upon an idividual, (for example, loss of a 

 finger, skill in using a revolver, a morphine habit) are called 

 "acquired characters." The great debate in biology for the 

 past seventy years has been on the question: Can acquired char- 

 acters be inherited? During these seventy years the opinion 

 of scholars has steadily grown stronger that acquired characters 

 cannot be inherited. 



This judgment of science seems harsh to conscientious parents. 

 It seems wicked to some hopeful social reformers, because it 

 seems to say, "No matter how much you improve the surround- 

 ings and education of this generation, none of the improvement 

 can be inherited by the next generation." It seems to say that 

 heredity is everything and environment nothing, so that men are 

 born to a certain condition in life. It seems to favor a caste 

 system where those unfortunately born cannot rise. Hence it is 

 disliked. People are always eager for proof that acquired char- 

 acters can be inherited. 



There are still a few of these bringers of glad tidings in the 

 laboratories. Though the vote of biologists is a very heavy 

 majority against them, the decision is not unanimous. And 

 recently some of the leading students of heredity have been 

 telling us that we don't know what "environment" means or how 

 environment may effect germ-cells or how characters are formed 

 in germ-cells. Only the other day a biologist declared to me, 

 "Within the last three years I have entirely revised my notion 

 of what the genes are." Hence the layman who wants to read 

 about heredity may find two noted scientists seeming to dispute 

 one another, and so may give up in confusion. 



I will try to show that the confusion is mostly a matter of 

 words. Biologists are not really at loggerheads about the main 

 points at issue, nor do their revised notions of the genes give 

 them very different conceptions of what children can inherit. 

 They are pretty well agreed on a theory of inheritance, and a 

 layman can understand what it is. 



If you wish knowledge, you must, in the first place, put out of 

 your mind all anger. A man who wants to uplift society or 

 improve his children cannot succeed by ramming his emotions 

 against the hard facts of biology. 



You must, in the second place, read a description of the way 

 every individual begins his life by the union of two cells. (The 

 best brief account that I know of is Chapter XVI of L. L. 

 Woodruff's "Foundations of Biology.") In this short article there 

 is only room to name the facts, without giving any explanation. 

 The egg (a cell 1/200 of an inch in diameter) contains within 

 itself, potentially, all the elements for the making of an entire 

 human being. The sperm (a cell only 1/8000 of an inch in 

 diameter) also contains all the elements of an entire person. 

 But neither cell can develop alone. A new human life does not 

 begin until the sperm has penetrated the egg. Then the elements 

 from the mother and the father are mingled in one cell; this 



divides into two cells; each of these two cells divides into two 

 others; and so, as the embryo develops, the cells increase in 

 number until there are millions of them. All the while the 

 embryo lives as a kind of parasite within the mother, having 

 its own system of blood-circulation. The number of cells in- 

 creases to billions. There are trillions of them at birth. 



Thus every one of us began life as a very small and infinitely 

 complex organism, which contained the characters inherited from 

 the father and mother. If the environment can ever affect heredity, 

 it must manage somehow to penetrate a parent's body and alter 

 the germ-cell in some definite corresponding way. The more 

 familiar science becomes with the powers of germ-cells, the 

 more difficult it is to imagine a way in which an environment 

 could get at them. 



No biologist believes nowadays that any effect of the environ- 

 ment on a woman's body or mind can enter into an embryo and 

 pioduce a corresponding alteration that can enter into the inher- 

 itance of her children. For example, if she is frightened by a 

 bear or a bright light, her child will not have claws or a white 

 spot on its body. If a hundred successive generations of Chinese 

 mothers bind their feet, or a hundred generations of Jewish 

 boys are circumcised, no effect of these long-continued bodily 

 changes is ever inherited. 



During the past thirty years the biologists have been steadily 

 abandoning the supposed cases of the inheritances of acquired 

 characters. It is not likely that any student of germ-cells now 

 believes that skill in penmanship can penetrate an egg and be 

 born in a child. No amount of training for the mile run can 

 cause a sperm to build larger muscles in an embryo. No amount 

 of education in religion or logarithms or atheism or burglary can 

 enter into a germ-cell and build more mathematical or bur- 

 glarious brains. The possible cases of inherited effects of training 

 are very few and not well accredited. 



Now that we have seen the field where practically all scholars 

 are unanimous in their opinion, we are prepared to look at the 

 edge of the field, at the boundary where the battles of conflict- 

 ing opinion rage. I can illustrate what all the battles are about 

 bv citing three extreme statements of eminent professors. In 

 each one you will see that the man has encountered a flood of 

 ignorance and foolishness, that he has done good by scornfully 

 exposing folly, but that, for the sake of making bis point, he 

 has gone further than the whole truth warrants. 



1. There is much folly talked by educated people about the • 

 inheritance of ways of behaving. They assume that gentlemanly 

 conduct or vicious habits of life are inherited. But John B. 

 Watson of Columbia finds no shred of evidence that any such 

 inheritance of conduct is possible. Conduct, he finds, is a matter 



of the training that an individual receives. Therefore Watson 

 makes the extreme statement: 



We have no real evidence of the inheritance of mental 

 traits ... I would feel perfectly confident in the ulti- 

 mately favorable outcome of careful upbringing of a healthy 

 well-formed baby born of a long line of crooks, murderers 

 and thieves, and prostitutes. . . . Give me a dozen healthy 

 infants, well-formed, and my own specified world to bring 

 them up in, and I'll guarantee to take any one at random 

 and train him to become any type of specialist I might se- 

 lect — into a doctor, lawyer, artist, merchant, chief. 

 Watson's extraordinary claim can never be proved or dis- 

 proved, because he cannot have his own specified world in which 

 to experiment. He has doubtless stated a fifty per cent truth, 

 for it seems likely that criminals and business men are largely 

 shaped by their environment, and not by inheritance of mental 

 traits. But most psychologists and biologists are compelled to 

 believe that many persons are born with such mental equipment 

 that they could never be great musicians or artists. 



2. The most important idea in twentieth-century study of 

 heredity has been "Mendelism," the theory of the way in which 

 bodily characters are formed in germ-cells by certain definite 



