of the body, and which not; the pains inflicted by fire, by missiles, by sharp instruments—­these, and various other pieces of information needful for the avoidance of death or accident, it is ever learning.  And when, a few years later, the energies go out in running, climbing, and jumping, in games of strength and games of skill, we see in all these actions by which the muscles are developed, the perceptions sharpened, and the judgment quickened, a preparation for the safe conduct of the body among surrounding objects and movements; and for meeting those greater dangers that occasionally occur in the lives of all.  Being thus, as we say, so well cared for by Nature, this fundamental education needs comparatively little care from us.  What we are chiefly called upon to see, is, that there shall be free scope for gaining this experience and receiving this discipline—­that there shall be no such thwarting of Nature as that by which stupid schoolmistresses commonly prevent the girls in their charge from the spontaneous physical activities they would indulge in; and so render them comparatively incapable of taking care of themselves in circumstances of peril.

This, however, is by no means all that is comprehended in the education that prepares for direct self-preservation.  Besides guarding the body against mechanical damage or destruction, it has to be guarded against injury from other causes—­against the disease and death that follow breaches of physiologic law.  For complete living it is necessary, not only that sudden annihilations of life shall be warded off; but also that there shall be escaped the incapacities and the slow annihilation which unwise habits entail.  As, without health and energy, the industrial, the parental, the social, and all other activities become more or less impossible; it is clear that this secondary kind of direct self-preservation is only less important than the primary kind; and that knowledge tending to secure it should rank very high.

It is true that here, too, guidance is in some measure ready supplied.  By our various physical sensations and desires, Nature has insured a tolerable conformity to the chief requirements.  Fortunately for us, want of food, great heat, extreme cold, produce promptings too peremptory to be disregarded.  And would men habitually obey these and all like promptings when less strong, comparatively few evils would arise.  If fatigue of body or brain were in every case followed by desistance; if the oppression produced by a close atmosphere always led to ventilation; if there were no eating without hunger, or drinking without thirst; then would the system be but seldom out of working order.  But so profound an ignorance is there of the laws of life, that men do not even know that their sensations are their natural guides, and (when not rendered morbid by long—­continued disobedience) their trustworthy guides.  So that though, to speak teleologically, Nature has provided efficient safeguards to health, lack of knowledge makes them in a great measure useless.