There could be no question about health.  It was true that I had suffered from no serious illness in my life, but London kept me in a normal state of low vitality.  I had constant headaches, fits of depression, and minor physical derangements.  I rarely knew what it was to wake in the morning with that clear joyousness of spirit which marks vigorous vitality.  A London winter I dreaded, and I had good reason for my dread.  When the fog lay on the town an unbearable oppression lay also on my spirits.  Imagination had little to do with this oppression; it was the physical result of lack of oxygen.  It was the same with my children; they grew pinched and bleached in face, and went about their little tasks with the slowness of old men.  It is stated, I believe, that London is the healthiest city in the world; no doubt it is true as regards the actual percentage of disease to the immense population, but statistics take no account of lowered vitality.  Without being actually ill, vitality may be reduced to a point at which existence becomes a kind of misery.  Alcohol dissolves for a time the cloud on the mind, the incubus upon the energies; and the relief is so great that men do not think of the price they pay for it.  No wonder public-houses are the landmarks of London locomotion; they are the Temples of Oblivion, where the devitalised multitudes seek to forget themselves, that they may regain the courage to live at all.

For myself, I had sense to know that stimulants of this kind were a remedy much worse than the disease.  The only stimulant, at once safe and effectual, which I needed was fresh air.  The moment I found myself among the hills a miraculous change was wrought in me.  I had not breathed that quick and vital air for an hour before a glow ran through my veins more delightful, and much more enduring, than the glow of wine.  A single night in some small cottage chamber—­where the very bed had a cool scent of flowers and lawns, where the open window admitted air fresh from pine forest and mountain streams, where the silence was so deep that one’s pulse seemed to tick aloud like a watch—­and I awoke a man renewed.  Six o’clock, or even five, was not too soon for all my little household to be astir.  We were all alike eager for the open air; for the walk, bare-footed, through the dewy grass to the mountain pool; for the shock and thrill of that green water into which we plunged delighted; and in those prolonged and pure ablations I think our spirits shared.  The bells of laughter rang the livelong day.  The cramped mind began to move again, and long abdicated powers of fancy and of humour were restored.  Equanimity of body brought evenness of temper; it was incredible to recollect how irritable we had been with one another in those ghastly days of London fog, when the very grating of a chair along the floor made the nerves jump.  Even the mind took new edge, for though I did not read much upon a holiday, yet I found that what I