Again, harm does not result from taking that active exercise which, as every child shows us, nature strongly prompts, but from a persistent disregard of nature's promptings; but the natural spontaneous exercise having been forbidden, and the bad consequences of no exercise having become conspicuous, there has been adopted a system of factitious exercise--gymnastics. That this is better than nothing we admit; but that it is an adequate substitute for play we deny. The truth is that happiness is the most powerful of tonics. By accelerating the circulation of the blood, it facilitates the performance of every function; and so tends alike to increase health where it exists, and to restore it when it has been lost. Hence the intrinsic superiority of play to gymnastics. The extreme interest felt by children in their games, and the riotous glee with which they carry on their rougher frolics, are of as much importance as the accompanying exertion; and as not supplying these mental stimuli gymnastics must be radically defective, and can never serve in place of the exercises prompted by nature. For girls as well as boys the sportive activities to which the instincts impel are essential to bodily welfare. Whoever forbids them, forbids the divinely-appointed means to physical development. We suffer at present from a very potent detrimental influence, which is excess of mental application, forgetting that nature is a strict accountant, and if you demand of her in one direction more than she is prepared to lay out, she balances the account by making a reduction elsewhere. We forget that it is not knowledge which is stored up as intellectual fat that is of value, but that which is turned into intellectual muscle. Worse still, our system is fatal to that vigour of physique needful to make intellectual training available in the struggle of life. Yet a good digestion, a bounding pulse, and high spirits are elements of happiness which no external advantages can outbalance.