VARIATION AND HEREDITY 29 



only the remaining 35 are not known to have been 

 chargeable on the rates. 



With such results before us we may well despair 

 of solving the problem of the poor law by administra- 

 tive changes alone. "To aim at economic change, 

 without seeking to change the quality of the human 

 element, is to waste good energy to no purpose." 



Many diseases which are themselves infectious, and 

 propagated by infection, are much more prevalent 

 or much more fatal in certain families than in others 

 much more so than the increased chances of infection 

 would warrant. While the disease itself is not here- 

 ditary, the predisposition to the disease is hereditary. 

 With a disease like tuberculosis, which is so prevalent 

 in this country that everyone is exposed more or less 

 to the risk of infection certainly everyone living in 

 the crowded quarters of towns the chances of escape 

 or attack depend very largely indeed on comparative 

 immunity or susceptibility. Pedigrees can be given 

 showing that, with specially tuberculous stock, an 

 enormous proportion of the individuals are attacked. 

 They would not have been attacked without infection, 

 but, equally, they would have escaped untouched had 

 they been more resistant to the disease. 



Certain types of mental defect are definitely here- 

 ditary. Two feeble-minded parents of these types 

 seem never to produce a normal child. Defective 

 families are well known in every district to those 

 who, with their eyes open, administer poor relief or 

 justice families of which some or all of the members, 

 generation after generation, have to be supported by 



