(b) Through an energetic campaign against rickets, to which only the predisposition can be inherited.
(c) Through the permeation of obstetrics with the spirit of eugenics, so that the obstetrician no longer proceeds according to a settled rule (living mother and living child), but in each separate case takes into consideration the interests of the race.
[HEREDITY AND EUGENICS IN RELATION TO INSANITY.]
(Abstract.)
By F. W. Mott, M.D., F.R.S.,
Physician to Charing Cross Hospital and Pathologist to the London County Asylums.
What is insanity? Every case of insanity is a biological problem, the solution of which depends upon a knowledge of what a man was born with—Nature—and what has happened after birth—Nurture. The increase of registered insanity in London; the causes of the increase. (1) The standard of insanity has been raised. (2) The increase of accommodation for reception of the insane. The diminishing death rate in asylums causing a progressive accumulation. The diminished number of recoveries. (3) The large proportion of old people admitted to asylums formerly in the infirmaries.
Nurture.—The correlation of pauperism, insanity and feeble-mindedness, alcohol, syphilis, and tuberculosis in relation to insanity and feeble-mindedness. Congenital mental deficiency as distinguished from hereditary mental deficiency. Chronic poisoning of the blood by these agencies in relation to a lowered specific vitality of the germ cells. Environment in relation to mental energy and will power.
Nature.—The study of pedigrees in hospital and asylum patients showing the importance of heredity in nervous and mental diseases. The nature of the neuropathic tendency; its transmission in different forms of nervous and mental disease in successive generations. Its latency and re-appearance in stocks. Relation of neurasthenia to the neuropathic taint. Conclusions arrived at in relation to heredity and insanity from a study by a card system of 3,118 related persons who are at present, or who have been, in the London County asylums. Among the 20,000 inmates at present resident, 715 are so closely related as parents and offspring or brothers and sisters. Nature is always trying to end or mend a degenerate stock if left to itself. Analysis of data regarding first attack of insanity in 464 parents and their 508 offspring; the signal tendency to the occurrence of the disease in a more intense form and at an earlier age in the offspring. This "antedating" or "anticipation" in relation to Nature's process of elimination of the unfit. Nearly 50 per cent. of the offspring affected 20 years earlier than the parent. The same found in uncles and aunts with nephews and nieces, only not nearly so marked. Seeing that the unfit are at present able to survive; does nature end or mend degenerate stocks, or have the lines of neuropathic inheritance only been partially cut off by this tendency to "anticipation"? What we want to know is: What is the fate of all the offspring of an insane parent or parents; for there are a great many facts which show that a disease may be latent and re-appear in a stock when the conditions of mating or environment are unfavourable? A collection of pedigrees is required which will prove conclusively that the offspring of insane parents, who are free from the insane manifestations during adolescence, will breed children who will not become insane. Supposing it were shown that cases discharged as recovered had the seeds of insanity, by the fact that their progeny were feeble-minded, epileptic, or insane, it would be a clear indication of taking measures to prevent them handing on the disease. Recurrent insanity—the birth of children in the sane intervals. Analysis of pedigrees with a dual neuropathic inheritance of maternal and paternal stocks compared with single neuropathic inheritance. Conclusion that a child born of neuropathic inheritance in both ancestral stocks stands, on an average, the chance of being insane four times as great as when only one stock is affected. Are there any types of insanity especially liable to be transmitted in the same form or another form? The prediction of the racial value of an individual inheritance can only be predicted by a study of what a man was born with—Nature, and what happened after birth—Nurture.