May 17, 19 1 7] 



NATURE 



227 



tions of selection show a continued progressive 

 movement of the racial character in the direction 

 of the selection, and indicate the existence of no 

 natural limit to the progress which selection can 

 make in changing the hooded character." Prof. 

 Castle's experiments show that there has been 

 over-hastiness in generalising from the results 

 reached by Johannsen and others. 



(2) The influence of the reproductive organs on 

 the secondary sex-characters differs in different 

 groups of animals A male crab that has suf- 

 fered parasitic castration puts on a number of 

 feminine characters and develops a small ovary. 

 In insects, on the other hand, the secondary sex- 

 characters seem to be quite independent of the 

 gonads. In male mammals the castration may 

 not be followed by any marked peculiarity in the 

 development of the secondary sex-characters, 

 though some of them may remain in an arrested 

 infantile condition. In the female mammal the 

 removal of the ovaries has very little effect on 

 the secondary sex-characters. What Mr. Goodale 

 has shown in regard to female birds (ducks and 

 hens) is just the opposite of what holds in 

 mammals. If the ovary be completely removed 

 the female puts on the secondary sex-characters 

 of the male — sometimes with startling complete- 

 ness. Some individuals, as the fine coloured 

 plates show, become nearly perfect replicas of 

 the male; others are imperfectly masculine. It 

 is interesting to notice that the masculine char- 

 acters induced on the ovariotomised female are 

 always like those of the male of the same breed. 

 With male birds the case is different. If the 

 gonads be removed, the majority of the secondary 

 sex-characters of the male develop, though a few 

 may remain in an infantile condition. What 

 have been sometimes called feminine characters 

 in castrated or abnormal males almost always 

 turn out to be juvenile characters. Another 

 interesting general fact is that castrated drakes 

 lose the power of developing the summer plumage. 



In thinking of the results of this carefully 

 worked-out piece of experimental investigation, 

 we see clearly that the internal secretions of the 

 gonads have a specific morphogenetic influence 

 on growing or active cells of the fxxly. As Mr. 

 Goodale says, the secretions must be considered 

 part of the influential environment of each cell. 

 But the further question arises whether the secre- 

 tion acts as a " modifier " affecting the factors 

 of a feminine character so that the result in 

 development is a masculine character ; or whether 

 the secretion acts as an " inhibitor " on one of 

 two alternative groups of factors, respectively 

 masculine and feminine, both present in the 

 female's genetic constitution. Thus in the duck 

 or hen the ovarian secretion inhibits the develop- 

 mental expression of the masculine plumage; in 

 the absence of the secretion the masculine features 

 find expression. It is too soon to decide between 

 these views ; Mr. Goodale appears to incline to the 

 former. It may be noticed incidentally that there' 

 is no conclusiveness in Mr. Goodale 's argument 

 against Dar\vin's theory of sexual selection. 



NO. 2481, VOL. 99] 



I "According to Darwin's theory the start was 

 j made from a dull-coloured monomorphic species, 

 I an assumption that is not in accord with the 

 ; nature of the female as shown by castration, 

 I since the brilliant male colours are only sup- 

 pressed in her. The only possible effect of selec- 

 ' tion, then, would be the uncovering of a condition 

 ! already present. But, by hypothesis, this condi- 

 ' tion did not pre-exist." But it is impossible to 

 argue from the constitution of a Rouen duck of 

 1916 to what may have been the constitution of 

 the female of distant ancestral types, before 

 masculine mutations — probably enough arising in 

 ' male-producing gametes — began to be included 

 in the common complement of hereditary factors, 

 forming a contingent of characters that normally 

 ' lie latent in female soil, and are normally patent 

 in male soil. 



(3)r Nearly a century and a half ago there 



drifted into an isolated valley in Z county in the 



1 United States "a nuirber of persons whose con- 



; stitution did not fit them for participation in a 



I highly organised society." Much of the original 



I stock was unsound, and in the relaxation of a 



\ primitive environment many of their progeny 



went from bad to worse. Constant inbreeding 



accentuated the deterioration. In 1874 the close 



j blood-relationship of a number of criminal types 



in the area referred to attracted the . attention of 



I Mr. R. L. Dugdale, an Englishman settled in 



New York, who was keenly interested in ques- 



I tions of social reform. In x^Tj he published his 



; well-known study, "The Jukes," in which he 



■ showed that a bad inheritance associated with 

 : deteriorative environmental conditions had resulted 

 I in a deplorable multiplication of criminality, 

 ' harlotry, and pauperism. The names he used in 



• his investigation were fictitious, but the chance 

 ; discovery of his original manuscript has made it 



possible for Dr. A. H. Estabrook to follow the 

 later history of the strains which Dugdale studied. 

 ; Starting from five sisters 130 years ago, the 

 j Jukes have become 2094, of whom 1258 were 

 ' living in 1915- "One-half of the Jukes were and 

 are feeble-minded, mentally incapvable of respond- 

 i ing normally to the expectations of society, 

 : brought up under faulty environmental conditions 

 which they consider normal, satisfied with the 

 ! fulfilment of natural passions and desires, and 

 i with no ambitions or ideals in life. The other 

 : half, perhaps normal mentally and emotionally, 

 has become socially adequate or inadequate, 

 depending on the chance of the individual reach- 

 ing or failing to reach an environment which 

 would mould and stimulate his inherited social 

 i traits." It must be noted that some have become 



• good citizens. 



Dr. Estabrook 's study shows that cousin- 

 matings of defective stock result in defective 

 \ offspring; that there is an hereditary factor in 

 ; licentiousness; that pauperism indicates physical 

 i or mental weakness; that all the Juke criminals 

 I were feeble-minded; that penal institutions have 



■ little beneficial influence upon these ; and that 

 ameliorative environment has markedly improved 



