264 SOCIAL HEREDITY AND SOCIAL EVOLUTION 



the holding of them together. The Roman empire 

 was limited in size by the possibility of coordination. 

 After its armies had extended far beyond the limits 

 of Italy there was produced an unwieldy mass which 

 it was impossible to hold long together. Even before 

 it became weak enough to be in danger of destruction 

 it broke into sections because it was too large to be 

 controlled as a unit. With the modern nation the 

 development of means for the rapid distribution of 

 information by steamships, railways, and telegraph 

 has vastly increased the possibility of coordination, 

 and consequently in the twentieth century nations 

 are possible which could not have held together at an 

 earlier date. But in every century the size of a 

 nation is limited by the possibility of a proper coor- 

 dination of its parts. 



Natural Selection Leads to Disintegration. — If we ask for 

 the forces that will make possible a lasting organi- 

 zation, we see, in the first place, that the struggle for 

 existence, as it occurs among animals and savages, 

 tends toward disintegration. It is true that some- 

 times animals live in peace with their own brothers, 

 though they may be at enmity with other animals. 

 A herd of buffalo lives in internal harmony, having 

 its struggle for existence with other animals and 

 with inanimate nature. Under these conditions a 

 certain amount of concentration is possible, so long 

 as food is abundant. But this is only because of the 

 internal harmony. Whenever the struggle for exist- 

 ence becomes one between animals of the same 

 species there is an inevitable tendency toward dis- 

 integration. Among all animals where the exigencies 

 of life lead to a rivalry of individuals there is a ten- 

 dency for the animals to live solitary lives. The same 



