212 HEREDITY AND SELECTION IN SOCIOLOGY 



/ integration of family life which marriage and the rearing of offs'pring 

 bring with them diminishes the liability to suicide. 



Although it seems certain that suicide is sometimes infectious 

 among individuals, it is equally certain that imitation has never 

 increased the total number of suicides to the extent of inter- 

 fering with what we have termed the social rate of suicide. As 

 M. Durkheim has remarked, " every society has, at each moment 

 of its history, a well-defined liability to suicide." ^ The relative 

 intensity of this liability, at any given moment, is measured 

 by comparing the total number of suicides with the total number 

 of the population of both sexes and of all ages. We shall find 

 the social rate of suicide to be constant among the population 

 of a country during long periods of time ; indeed, the suicide- 

 rate is more constant than the general mortality-rate.* We 

 shall find, also, that the variations of the suicide-rate appear to 

 be governed by certain well-defined laws. Thus, if we examine 

 the statistics of suicide in the various countries of Europe 

 during a given period, we shall find, in the first place, a steady 

 rise all over the Continent ; we shall find, also, certain other 

 ^phenomena manifested — for instance, a marked decrease in the 

 suicide-rate in 1848 in the three countries most affected by 

 the Eevolution, France, Prussia, and Denmark; a steady rise 

 in the suicide-rate in France from 1860 onwards — ^that is to say, 

 from the most brilliant days of the second Empire on, until 

 1868, when the maximum is attained, followed by a sudden fall 

 in 1869, in the year of political crisis and tension which preceded 

 the war with Germany ; an equally steady rise in the suicide-rate 

 of Prussia, from 1866, the date of the triumph of Sadowa, on 

 to 1870, when a brusque decrease is noticeable ; and a steady 

 rise in the suicide-rate of England and Wales, beginning in 1868, 

 after the commercial revolution brought about by the new 

 commercial treaties. Thus, these figures teach us already one 

 1 E. Durkheiin, op. cit., p. 10. 



