CHAPTER V.

HEREDITY AND STERILITY.

General resemblance of children to their parents-Galton's statistics in reference to the transmission of genius-Darwin's remarks on the subject-The question of generation more important than that of education-Lord Somerville on the breeding of sheep-Sir John Sebright's experience in relation to pigeons -Fruitless marriages— Supposed evil results of consanguinity of parents-Sterility has a bearing on our subject-Sterility more frequently relative than absolute-Various instances-Unilateral hybridity-Its bearing on the law of sex-Sterility from a mistaken choice in marriage— Cerebral development a check to fecundity-Antagonism between the nervous and reproductive systems-Darwin's testimony in support of this-Late marriages the most prolific-Combe on hereditary transmission-The author's views on this point-Parental transmission of faculties-Hereditary gout, consumption, insanity, etc.-Influence of age of parents on offspring-Darwin on pangenesis-Deterioration of nations-Vital importance of the law of heredity-Professor Huxley and Mr. Galton on parental influence-Responsibility of parents for the health and moral tone of children.

COMMON observation goes to prove that children

generally, more or less, resemble their parents, and science has given endless proofs of the inheritance of special qualities, and even of chance peculiarities reappearing generations after the original progenitor has passed away. And yet there is some uncertainty on the subject, for Mr. Francis Galton, FR.S., has found reason to write a work, with a mass of most carefully compiled statistics, to show that genius, on the whole, tends to be hereditary. And Darwin makes the following statement in the Origin of Species:" The laws governing inheritance are for the most part unknown. No one can say why the

same peculiarity in different individuals of the same species, or in different species, is sometimes inherited. and sometimes not so; why the child often reverts in certain characteristics to its grandfather or grandmother or more remote ancestor; why a peculiarity is often transmitted from one sex to both sexes, or to one sex alone, more commonly, but not exclusively to the like sex." It seems, therefore, necessary to devote a few pages to examine how far the features, disposition, and peculiarities of a parent may be looked for in the children-more especially as this will help us in determining what are the causes which influence sex.

Great attention has been recently given to education; it is looked upon as a sovereign remedy for crime and many other diseases of the body politic. But probably the most urgent question of the times is this: Is not generation of more consequence than education? None can fail to see the incomparable advantage which the preceptor of the child Moses would enjoy compared with one who should attempt to guide aright the stripling Ishmael. Were Socrates

and Nero alike in infancy? or St. Vincent and Pope Alexander VI.? Lady Jane Grey and Catharine of Russia? Was it education merely that made the contrast between Newton and Boswell? or Henry Kirke White and Edgar Allen Poe? between Howard the philanthropist and Robespierre the human fiend? In improving the breed of domestic animals, is the best attention given to the training or to the blood?

It has been truthfully remarked that "education is well advanced, but we are beginning to see that it is like the ancient writing of manuscripts, a slow pro

cess with many drawbacks. We labour to perfect the individual, but what we want is, the art of multiplying copies of our best work. Education is waiting for its printing press, which is, scientific propagation." Lord Somerville, in speaking of what breeders have done for sheep, says: "It would seem as if they had chalked out upon a wall a form, perfect in itself, and then had given it existence." Sir John Sebright, so well known as a skilful breeder, says of pigeons, that "he will produce any given feathers in three years, but that he needs six years to obtain head and beak." It is indisputable that vastly more care and thought are devoted to the production of perfect horses, cattle, sheep, and pigeons, than to men and women.

And now let us look for a moment at the question of sterility, which indirectly has a bearing on the subject of sex of offspring. Here, again, we are met by many theories and much conflicting evidence.

Many marriages are fruitless owing to the early deaths of children or to the sterility of the parents, and many theories have been advanced to explain these facts. Consanguinity of parents is with us believed to be the fruitful cause of idiotcy, lunacy, disease, and early death; and when close intermarriage is continued for generations, these results are believed to be rendered more pronounced. The decay and total extinction of noble families are attributed to this cause. Yet the Jews are most strict in this matter of intermarriage, and they continue to be a remarkably healthy and clever race.

Sterility is relative rather than absolute, unless it

be due to some malformation or infirmity. Perhaps the best evidence to bring out this relative character is that afforded by the intercrossing of races. Some, indeed most, races are fertile "inter se," so far as the first cross is concerned. But even with such, where the most perfect hybridity seems to exist, M. Broca assures us-and he has given more attention to this subject than perhaps any other writerthat the mulattoes resulting from the intercrossing of blacks and whites are often sterile with each other, or at least far less fertile than when united to one of the parent races. Sometimes this sterility is not seen until the second or third generation, but it is almost always manifested sooner or later. When the races intercrossed are more remote, a curious phenomenon is presented, called unilateral hybridity, i.e., the union of the superior male with the inferior female produces offspring freely, but the converse union is seldom fertile. Again,-and on this point M. Broca is supported by many writers whom he quotes,-instances occur where the union of two races exceedingly remote is nearly always sterile. This is notably the case with the Anglo-Saxons and the indigenous races of Australia. At first sight the foregoing may appear to be remote from the subject of this chapter, but the fact sought to be established is that sterility depends, in part at least, upon great diversity in organization. The special value of this important point in connection with my theory will be fully considered in a subsequent chapter.

Further as to this relative character of sterility. An individual may possibly have inherited or in

* Chap. VI., p. 144.

some way acquired a constitution with one or more organs so developed-the brain, for example-that a union with one of the opposite sex having a similar excess will surely prove fruitless; but if united to one with a predominant nutritive system, a fair offspring may be the result. Again where the nutritive system. greatly prevails in both parents they are almost sure to die childless. These consequences, however, not only result from the excessive development of any one or two organs, but also from every undue divergence from the normal condition.

The late Mr. W. R. Greg believed cerebral development to be a check to fecundity, and he supported this view by citing the lower races of mankind, such as the negroes, and the lower animals. Carey also states the same thing with some modifications. He says: "The general law of life throughout all the classes, order, genera, species, and individuals, may be thus stated :

"The nervous system varies directly as the power to maintain life.

"The degree of fertility varies inversely as the development of the nervous system,-animals with larger brains being always the least, and those with smaller ones the most prolific.

'The power to maintain life and that of pro creation antagonize each other-that antagonism tending perpetually towards the establishment of an equilibrium."

Carey also says that the antagonism between the nervous and reproductive systems is universally recognized. Thus the negroes in America with a low order of intellect are most prolific, as are also the