Certainly the carriage of an individual, outer symptom of the inner tonus among his muscles and tendons, may be said to be as distinctively an endocrine affair as the color of his skin.

The relative ratios of tonus in these smaller internal secretion balances are of the utmost significance as causes of differences in the vegetative apparatus, which are the basis of differences in structure, power, and character between individuals.

A similar mechanism for the tonus of the other members of the vegetative system, and how they determine consciousness and behaviour is understandable.