Statistics is a science which ought to be honourable, the basis of many most important sciences; but it is not to be carried on by steam, this science, any more than others are; a wise head is requisite for carrying it on.

There are various causes for the generation of force: a tensed spring, an air current, a falling mass of water, fire burning under a boiler, a metal that dissolves in an acid—one and the same effect can be produced by means of all these various causes. But in the animal body we recognise only one cause as the ultimate cause of all generation of force, and that is the reciprocal interaction exerted on one another by the constituents of the food and the oxygen of the air. The only known and ultimate cause of the vital activity in the animal as well as in the plant is a chemical process.