112 A STUDY IN HEREDITY 



which is practically unlimited in quantity and 

 extremely strong in solution. Evolution against 

 disease followed precisely the same steps. A high 

 degree of civilisation is impossible to any race 

 unless it has previously undergone extensive 

 evolution against certain microbic diseases. 

 Presently we shall see that advanced civilisation is 

 equally impossible to all races which have not 

 undergone as considerable an evolution against 

 alcohol. 



