Eugenics and Other Evils, by G.K. Chesterton (Cassell : 1922), p.76-77.
The thing that really is trying to tyrannise through government is Science. The thing that really does use the secular arm is Science. And the creed that really is levying tithes and capturing schools, the creed that really is enforced by fine and imprisonment, the creed that really is proclaimed not in sermons but in statutes, and spread not by pilgrims but by policemen — that creed is the great but disputed system of thought which began with Evolution and has ended in Eugenics. Materialism is really our established Church; for the Government will really help it to persecute its heretics. Vaccination, in its hundred years of experiment, has been disputed almost as much as baptism in its approximate two thousand. But it seems quite natural to our politicians to enforce vaccination; and it would seem to them madness to enforce baptism.