VARIATION AND HEREDITY 25 



that the class association by which we obtain segrega- 

 tion of type and specialization of innate endowments 

 has a real evolutionary meaning, corresponding to 

 the increasing complexity of social requirements, and 

 is probably playing some useful part in the biological 

 development of the human race. 



Turning to the other side of the picture, we are 

 met by terrible instances of families in which physical 

 unsoundness, mental defect and criminal propensities 

 are inherited from generation to generation in unfail- 

 ing succession. The classical instance is the family 

 to which the pseudonym of " Jukes " has been given 

 by their historian. The pedigree contains some 830 

 known individuals, all descended from five sisters 

 born about 1760. A large proportion of these in- 

 dividuals have been in prison, some of them for 

 serious crimes. Frequently, the women have con- 

 sorted with criminals of other stocks. Many of the 

 race have been paupers, supported wholly or partly 

 by the community. The total direct loss to their 

 country caused by this one family has been estimated 

 at about 260,000, while the indirect loss is probably 

 much greater. 



The study of criminal types has of late years become 

 a branch of penal jurisprudence, and owes much of 

 its success to the labours and stimulus of the Italian 

 criminologist, Cesare Lombroso. The modern school 

 of criminology has made a careful investigation of 

 criminals of various types, and has shown that they 

 exhibit numerous anomalies in facial structure, in 

 skeletal peculiarities, in nervous conditions which 



