If the reverse takes place, and the demand be suddenly increased, the result is weakness, debility, and finally disease; though precisely the same amount of work might have been done, not only with safety but with positive advantage, provided the increase of the demand had been gradual.
Is there any country in the world equal to America in the irregularity and spasmodic nature of the demands which society makes upon its women? Are there any girls in the world so ready to rush headlong into all kinds of exercise, mental or physical, which may be recommended to them, as our American girls? It is a pity that, to balance our greater amount of fiery energy in the matter of education, we have not a sounder philosophy.
Once more, physical life is only a balance of forces, as spiritual life is a series of choices, and the question is not simply how much intellectual or brain work we are doing. This question cannot justly be considered apart from the other inquiry, of how much appropriate material we are supplying for the use of the brain. We cannot judge whether the amount of force expended be healthful or unhealthful till we know how much force has been and can be generated. There is undoubtedly a limit to this last factor in our problem, but if we do not exceed this limit in our expenditure, it seems unquestionable, that the more brain work we do, the better will it be for the entire system, and the stronger will be our health, this being only our power actively to resist the destructive forces of nature.
The nervous system, at the head of which stands the brain, is undoubtedly the regent of the monarchy of the body, whose sovereign is the thinking spirit; and all the organs in a well-regulated body should be worked in the interest of the organ of thought, as servants for a wise and watchful master. It seems sometimes as if we were in danger of forgetting that though "the eye cannot say unto the hand, I have no need of thee, nor again, the head to the feet, I have no need of you," there will come a time when the thinking spirit, grown to full stature, shall say to all of them, "I have no need any longer of any of you."
The consideration of the subject of Ventilation properly comes under this division, for pure air is as much food for the body, as meat or bread. This whole matter, however, seems to be practically not well understood, if we may judge from the results so far, and no extended discussion of the means will be in place there. It is sufficient simply to indicate its immense importance. But that bad air is likely to be a more active cause of disease in America than elsewhere seems true, for in no other country are furnaces and closed fire-places in so general use. Moreover, the women and girls who spend most of their lives in the house, will be expected to show the evil effects more than the men and boys, who do not. The practical suggestions on this point are apparent to every one.