The infancy and childhood of commencing old age have the same ingenuous simplicity and delightful unconsciousness about them that the first stage of the earlier periods of life shows. The great delusion of mankind is in supposing that to be individual and exceptional which is universal and according to law. A person is always startled when he hears himself seriously called an old man for the first time. Nature gets us out of youth into manhood, as sailors are hurried on board of vessels,--in a state of intoxication. We are hustled into maturity reeling with our passions and imaginations, and we have drifted far away from port before we awake out of our illusions. But to carry us out of maturity into old age, without our knowing where we are going, she drugs us with strong opiates, and so we stagger along with wide open eyes that see nothing until snow enough has fallen on our heads to rouse our comatose brains out of their stupid trances. There is one mark of age that strikes me more than any of the physical ones;--I mean the formation of _Habits_. An old man who shrinks into himself falls into ways that become as positive and as much beyond the reach of outside influences as if they were governed by clockwork. The _animal_ functions, as the physiologists call them, in distinction from the _organic_, tend, in the process of deterioration to which age and neglect united gradually lead them, to assume the periodical or rhythmical type of movement. Every man's _heart_ (this organ belongs, you know, to the organic system) has a regular mode of action; but I know a great many men whose _brains_, and all their voluntary existence flowing from their brains, have a _systole_ and _diastole_ as regular as that of the heart itself. Habit is the approximation of the animal system to the organic. It is a confession of failure in the highest function of being, which involves a perpetual self-determination, in full view of all existing circumstances. But habit, you see, is an action in present circumstances from past motives. It is substituting a _vis a tergo_ for the evolution of living force.