EUGENICS 1 7
action of the environment on him tend in any way to affect the offspring subse- quently born to him. Thus, for example, does good health in an individual tend to benefit his offspring? Does his ill-health tend to enfeeble them?
It is generally assumed that changes in the parents do tend to influence the inborn traits of offspring. Thus we have heard much of the degeneracy which it is alleged is befalling our race owing to the bad hygienic conditions under which it dwells in our great growing cities. The assumption is made that the race is being so injured by the bad conditions that the descendant of a line of slum- dwellers, if removed during infancy to the country, would, on the average, be inferior physically to the descendant of a line of rustics ; whereas, contrariwise, the descendant of a line of rustics, if removed during infancy to the slums would be superior physically to the majority of the children he would meet there.
I believe this assumption to be a totally unwarrantable one. It is founded OK a confusion between inborn and acquired traits. Of course, the influences which act on a slum-bred child tend to injure him personally. But there is no certain evidence that the descendant of a line of slum-dwellers is on the average inferior to the descendant of a line of rustics whose parents migrated to the slums just after his birth. I believe in fact, that while a life in the slums deteriorates the individual, it does not affect directly the hereditary tendencies of the race in the least. A vast mass of evidence may be adduced in support of this contention. Slums are not a creation of yesterday. They have existed in many countries from very ancient times. Races that have been most exposed to slum life canot be shown to be inferior physically and mentally to those that have been less or not at all exposed. The Chinese, for example, who have been more exposed, and for a longer time, to such influences than any other people, are physically and mentally a very fine race, and certainly not inferior to the Dyacks of Borneo, for example.
There IF also a mass of collateral evidence. Thus Africans and other races have been literally soaked in the extremely virulent and abundant poison of malaria for thousands of years. We know how greatly malaria damages the individual. But Africans have not deteriorated. Like the Chinese, physically, at any rate, they are a very fine race. Practically speaking, every negro child suffers from malaria, and may perish of it. But while the sufferings of the negroes from malaria have produced no effect on the race, the deaths of negroes from malaria have produced an immense effect. The continual weeding out, during many generations, of the unfittest has rendered the race pre-eminently resistant to malaria ; so that negroes can now flourish in countries which we, who have suffered very little from malaria, find it impossible to colonize. Similarly, the inhabitants of northern Europe have suffered greatly for thousands of years from consumption, especially in places where the population has been dense where there have been many cities and towns, and therefore slums. They also have not deteriorated ; they have merely grown pre-eminently strong against con- sumption. They are able to live, for example, in English cities, in which con- sumption is very rife, and which individuals of races which have been less exposed to the disease find as dangerous as Englishmen find the west coast of Africa.
During the last four hundred years consumption has spread very widely, and now no race is able to dwell in cities and towns, especially in cold and temperate climates, that has not undergone evolution against it. In other words, no race is capable of civilization that has not undergone evolution against consumption, as well as against other diseases and influences, deteriorating to the individual, which civilization brings in its train. Many biologists and most medical men believe that influences acting on parents tend directly to alter the hereditary ten- dencies of oil spring. In technical terms, they believe that variations are caused by action of the environment. How they contrive to do so in the face of the massive and conclusive evidence afforded by the natural history of human races in relation to disease is beyond my comprehension. How could a race undergo evolution against malaria (for example), if parental disease altered and injured the hereditary tendencies of the offspring. How could natural selection select, if all the variations presented for selection were unfavorable. The observations on
