402 



NA TURE 



[February 2J5, 1905 



ablo authority issuing eugenic certificates to candidates for 

 them. They would imply more than an average share of 

 the several qualities of at least goodness of constitution, 

 of physique, and of mental capacity. 



'1 he discussion on the papers was opened by Dr. Haddon, 

 who said Mr. Galton sought to establish a science of 

 eugenics, he took it, because the postulates of eugenics 

 were an inevitable corollary from the general doctrine of 

 organic evolution — in the building up of which Mr. Galton 

 had played a notable part. The evolution of the species 

 having reached a self-conscious stage in man, it followed 

 of necessity that increasingly rational and coordinated 

 attempts should be made to guide and direct the evolu- 

 tionary process towards definable and verifiable ideals. It 

 was, as he understood it, the aim of eugenic studies to 

 ascertain the means available for this rational guidance 

 of human evolution, and the defining of the ideals towards 

 which it should be directed. There was ample warrant in 

 anthropological data for the assumption that in the de- 

 velopment of marriage customs there was a tendency 

 towards adaptation to higher social purposes. 



Dr. F. VV. Mott said there were two general ways 

 towards the rational improvement of the stock : — (i) by 

 checking the reproduction of the unfit, and (2) by 

 encouraging the reproduction of the fit. For the former 

 purpose the readiest means would be the segregation of 

 defective children while quite young, and the curtailment 

 of their social privileges as they grew to maturity. As 

 regards means towards the encouragement of fertility in 

 the higher types, he suggested as an initial tentative in 

 practical measures a further development of the present 

 system of marriage registration. Why, for instance, 

 should not medical as well as legal certificates of marriage 

 be procurable at registry offices? The former would be 

 of the nature of a bill of health, certifying that the con- 

 tracting parties reached a certain standard of hygienic 

 requirement. Such certificates would of course be volun- 

 tary, but since they would be valuable not only to their 

 possessors but also to their children, they would tend to 

 come into general usage. In any case he considered it a 

 matter of national importance that Mr. Galton's concep- 

 tion of eugenics should be most seriously considered. The 

 first desideratum -was to get it accepted as a legitimate and 

 hopeful study. 



Mr. Ernest Crawley said Mr. Galton's paper showed how 

 anthropological studies could be made fruitful in practical 

 politics. .Sociology should be founding its science of 

 eugenics upon anthropology, psychology, and physiology. 

 He hoped that while chiefly considering the normal in- 

 dividual' it would not forget the special claims of those 

 abnormal persons whom we call geniuses. In a well 

 ordered State they should be considered before the de- 

 generate and the diseased. As regards marriage customs, 

 he took it as an assured generalisation of anthropological 

 science that there are two permanent polar tendencies in 

 human nature, first against unions in the same home, and 

 secondly against too promiscuous marriage. Many customs 

 assumed by early anthropologists as normal types were, 

 he believed, mere sports — such as group-marriage, and 

 marriage of brother and sister. Polygamy he believed to 

 be an example of a certain tendency in man to confuse 

 sexual {i.e. organic), with matrimonial (i.e. social) concerns. 

 They must beware of this confusion, and therefore be on 

 their guard against its possible effects in studying eugenics. 

 Mr. Galton's suggestion that religion was called upon 

 to play a part in the development of eugenics he con- 

 sidered to be a sound deduction from history and anthro- 

 pology. In the sanctificatlon of marriage, religion had 

 one of its earliest and greatest functions ; and as primitive 

 religion, in this as in other respects, was based upon the 

 best knowledge of primitive times (i.e. upon primitive 

 science), so the most developed form of religion should be 

 illuminated by the most advanced form of knowledge (i.e. 

 by contemporary science). 



Dr. E. Wcstermarck said he entirely agreed with Mr. 

 Galton's contention that restrictions in marriage as they 

 e.xisted in the simpler social formations, so they might be 

 further modified and developed for eugenic purposes 

 amongst the mo.st highly civilised peoples. The germ of 

 eugenic intentions was well seen amongst savage and 

 barbarian peoples in those customs which imposed a test 



NO. 1843, VOL 71] 



of fitness on the husband before marriage. In Kaffir 

 tribes, for instance, a man may not marry until he has 

 demonstrated his strength and courage and competence 

 in the chase by killing a rhinoceros. In the Malay Archi- 

 pelago there are peoples where the marriage test consists 

 in the collection of a number of skulls from hostile tribes. 

 .Vmong the Arabs of Upper Egypt, the young aspirant to 

 marriage must evidence his courage and self-control by 

 suffering — with smiling countenance — a severe ordeal of 

 whipping by the relatives of the bride. He considered that 

 on this question of marriage, whereby the individual was 

 brought into bpth organic and social relation with the 

 species, moral teachers had before them one of the greatest 

 of tasks, in inculcating a keener sense of foresight in the 

 individual. There was perhaps hardly any other point in 

 which the moral consciousness of civilised men stood in 

 greater need of intellectual training. 



As contributions to the discussion, a considerable number 

 of written communications were received, from the follow- 

 ing amongst others: — Dr. Havelock Ellis, Mr. A. H. 

 Huth, Dr. Max Nordau, and Profs. Yves Delage, J. G. 

 McKendrick, Posada, Sergi, Steinmetz, Tonnies, and 

 Weismann. The last named raised the question whether, 

 when a hereditary disease like tuberculosis has made its 

 appearance in a family, it is afterwards possible for it to 

 be banished entirely from this or that branch of the family, 

 or whether, on the contrary, the progeny of those members 

 who appear healthy must not sooner or later produce a 

 tuberculous progeny. He himself considered that a tainted 

 stock might produce a branch entirely free from that 

 specific disease. 



Mr. Galton, in the course of his reply, said it gave him 

 satisfaction to find that no one amongst his critics had 

 impugned the conclusion which his memoir on " Restric- 

 tions in Marriage " was written to justify. 



THE ABSORPTION OF LIGHT BY THE 

 ATMOSPHERE.' 

 'T'HE great attention that has been paid during the last 

 few years to the subject of photometry has brought 

 into prominence the problem of the amount of light absorbed 

 by the atmosphere. At the same time, the improvement 

 that has taken place in the instrumental means, which 

 renders possible the detection of minute changes in lustre, 

 has required the use of accurate corrections by which the 

 effect of the earth's atmosphere can be eliminated from 

 the observations. The corrections which have been applied 

 to photometric measures have been based generally on 

 empirical or interpolation methods rather than on a strictly 

 physical basis. There are several reasons which have con- 

 tributed to this unsatisfactory condition of the problem. 

 The difficulty of computing the length of the path of the 

 ray of light in its passage through our atmosphere, the 

 want of homogeneity in the constitution of the atmosphere 

 itself, our ignorance of the law of the temperature gradient 

 at considerable heights above the surface, and of the dis- 

 tribution of water and dust particles near the surface, have 

 all complicated a subject the theory of which under ideal 

 limiting conditions may not be very difficult. Bouguer left 

 a very satisfactory theory, based, however, on the assump- 

 tion that the path of the ray was rectilinear. Laplace 

 attacked the subject from- the side of the theory of refrac- 

 tion, but practically did not much advance it. From that 

 time onward, the question has rather been left in the hands 

 of observers, who have been content to make their observ- 

 ations homogeneous by the employment of an interpolation 

 formula, based on the results of their actual practice. 



Dr. A. Bemporod thinks that the time has come for the 

 discussion of a physical theory of the extinction of light in 

 the atmosphere, and certainly his pamphlet bearing this 

 title is a most welcome contribution to this subject. It 

 may be that in some sense it is a premature effort. That 

 is to say, that the data for a complete solution of the 

 problem do not exist. The series of observations which are 

 now being conducted by means of kites and balloons, and 

 which have for their object the examination of the different 



1 "Zur Theorie der Extinklion des I.ichtes in der Erdatmosphiire." By 

 nr. A, Bemporod. Pp. 78. (Vliueilungen der Grossh. Slern«.irle zu 

 Heidelberg.) 



