I have read with very great pleasure the letter of Mr. Bryant…. Let me observe that while the modes of my own life and those of Mr. Bryant very much accord, in a few particulars they differ, as, I suppose, must be the case in almost any two individuals. Mr. Bryant never takes coffee or tea. I regularly take both, find the greatest refreshment in both, and never experienced any deleterious effects from either, except in one instance, when, by mistake, I took a cup of tea strong enough for ten men. On the contrary, tea is to me a wonderful refresher and reviver. After long-continued exertion, as in the great pedestrian journeys that I formerly made, tea would always, in a manner almost miraculous, banish all my fatigue, and diffuse through my whole frame comfort and exhilaration, without any subsequent evil effect.

I am quite well aware that this is not the experience of many others, my wife among the number, on whose nervous system tea acts mischievously, producing inordinate wakefulness, and its continued use, indigestion. But this is one of the things that people should learn, and act upon, namely, to take such things as suit them, and avoid such as do not. It is said that Mithridates could live and flourish on poisons, and if it be true that tea or coffee is a poison, so do most of us. William Hutton, the shrewd and humorous author of the histories of Birmingham and Derby, and also of a life of himself, scarcely inferior to that of Franklin in lessons of life-wisdom, said that he had been told that coffee was a slow poison, and, he added, that he had found it very slow, for he had drunk it more than sixty years without any ill effect My experience of it has been the same.

Mr. Bryant also has recourse to the use of dumb-bells, and other gymnastic appliances. For my part, I find no artificial practices necessary for the maintenance of health and a vigorous circulation of the blood. My only gymnastics have been those of Nature—walking, riding, working in field and garden, bathing, swimming, etc. In some of those practices, or in the amount of their use, Nature, in my later years, has dictated an abatement. In Mr. Bryant's abhorrence of tobacco, I fully sympathize. That is a poisoner, a stupefier, a traitor to the nervous system, and, consequently, to energy and the spirit of enterprise, which I renounced once and for ever before I reached my twentieth year. The main causes of the vigor of my constitution and the retention of sound health, comfort, and activity to within three years of eighty, I shall point out as I proceed. First and foremost, it was my good fortune to derive my existence from parents descended on both sides from a vigorous stock, and of great longevity. I remember my great-grandmother, an old lady of nearly ninety; my grandmother of nearly as great an age. My mother lived to eighty-five, and my father to the same age. They were both of them temperate in their habits, living a fresh and healthy country life, and in enjoyment of that tranquillity of mind which is conferred by a spirit of genuine piety, and which confers, in return, health and strength.

The great destroyers of life are not labor and exertion, either physical or intellectual, but care, misery, crime, and dissipation. My wife derived from her parentage similar advantages, and all the habits of our lives, both before and since our marriage, have been of a similar character. My boyhood and youth were, for the most part, spent in the country; and all country objects, sports, and labors, horse-racing and hunting excepted, have had a never-failing charm for me. As a boy, I ranged the country far and wide in curious quest and study of all the wild creatures of the woods and fields, in great delight in birds and their nests, climbing the loftiest trees, rocks and buildings in pursuit of them. In fact, the life described in the "Boy's Country Book," was my own life. No hours were too early for me, and in the bright, sunny fields in the early mornings, amid dews and odour of flowers, I breathed that pure air which gave a life-long tone to my lungs that I still reap the benefit of. All those daily habits of climbing, running, and working developed my frame to perfection, and gave a vigor to nerve and muscle that have stood well the wear and tear of existence. My brain was not dwarfed by excessive study in early boyhood, as is too much the case with children of to-day. Nature says, as plainly as she can speak, that the infancy of all creatures is sacred to play, to physical action, and the joyousness of mind that give life to every organ of the system. Lambs, kittens, kids, foals, even young pigs and donkeys, all teach the great lesson of Nature, that to have a body healthy and strong, the prompt and efficient vehicle of the mind, we must not infringe on her ordinations by our study and cramping sedentariness in life's tender years. We must not throw away or misappropriate her forces destined to the corporeal architecture of man, by tasks that belong properly to an after-time. There is no mistake so fatal to the proper development of man and woman, as to pile on the immature brain, and on the yet unfinished fabric of the human body, a weight of premature and, therefore, unnatural study. In most of those cases where Nature has intended to produce a first-class intellect, she has guarded her embryo genius by a stubborn slowness of development. Moderate study and plenty of play and exercise in early youth are the true requisites for a noble growth of intellectual powers in man, and for its continuance to old age.

My youth, as my boyhood, was spent in the country, and in the active exercise of its sports and labors. I was fond of shooting, fishing, riding, and walking, often making long expeditions on foot for botanical or other purposes. Bathing and swimming I continued each year till the frost was in the ground and the ice fringed the banks of the river. As my father farmed his own land, I delighted in all the occupations of the field, mowing and reaping with the men through the harvest, looking after sheep and lambs, and finding never-ceasing pleasure in the cultivation of the garden.

When our literary engagements drew us to London, we carefully avoided living in the great Babel, but took up our residence in one of its healthy suburbs, and, on the introduction of railways, removed to what was actual country. A very little time showed us the exhausting and unwholesome nature of city life. Late hours, heavy dinners, the indulgence of what are called jovial hours, and crowded parties, would soon have sent us whither they have sent so many of our literary contemporaries, long, long ago. After an evening spent in one of the crowded parties of London, I have always found myself literally poisoned. My whole nervous system has been distressed and vitiated. I have been miserable and incapable the next day of intellectual labor. Nor is there any mystery about this matter. To pass some four or five hours in a town, itself badly ventilated, amid a throng of people just come from dinner, loaded with a medley of viands, and reeking with the fumes of hot wines—no few of them, probably, of very moral habits, was simply undergoing a process of asphyxia. The air was speedily decomposed by so many lungs. Its ozone and oxygen were rapidly absorbed, and in return the atmosphere was loaded with carbonic acid, carbon, nitrogen, and other effluvia, from the lungs and pores of the dense and heated company; this mischievous matter being much increased from the products of the combustion of numerous lamps, candles, and gas-jets.

The same effect was uniformly produced on me by evenings passed in theatres, or crowded concert or lecture rooms. These facts are now well understood by those who have studied the causes of health and disease in modern society; and I am assured by medical men that no source of consumption is so great as that occasioned by the breathing of these lethal atmospheres of fashionable parties, fashionable theatres, and concert and lecture halls; and then returning home at midnight by an abrupt plunge from their heat into damp and cold. People have said to me, "Oh! it is merely the effect of the unusual late hour that you have felt!" But, though nite hours, either in writing or society, have not been my habit, when circumstances of literary pressure have compelled me occasionally to work late, I have never felt any such effects. I could rise the next day a little later, perfectly refreshed and full of spirit for my work.

Another cause to which I attribute my extraordinary degree of health, has been not merely continued country exercise in walking and gardening, but, now and then, making a clean breach and change of my location and mode of life. Travel is one of the great invigorators of the system, both physically and intellectually. When I have found a morbid condition stealing over me, I have at once started off on a pedestrian or other journey. The change of place, scene, atmosphere, of all the objects occupying the daily attention, has at once put to flight the enemy. It has vanished as by a spell. There is nothing like a throwing off the harness and giving mind and body a holiday—a treat to all sorts of new objects. Once, a wretched, nervous feeling grew upon me; I flung it off by mounting a stage-coach, and then taking a walk from the Land's End, in Cornwall, to the north of Devon. It was gone for ever! Another time the "jolly" late dinners and blithely-circulating decanter, with literary men, that I found it almost impossible to avoid altogether without cutting very valuable connections, gave me a dreadful dyspepsia. I became livingly sensible of the agonies of Prometheus with the daily vulture gnawing at his vitals. At once I started with all my family for a year's sojourn in Germany, which, in fact, proved three years. But the fiend had left me the very first day. The moment I quitted the British shore, the tormentor quitted me. I suppose he preferred staying behind, where he was aware of so many promising subjects of his diabolical art. New diet, new and early hours, and all the novelties of foreign life, made his approach to me impossible. I have known him no more, during these now thirty years.

Eighteen years ago I made the circumnavigation of the globe, going out to Australia by the Cape of Good Hope, and returning by Cape Horn. This, including two years of wandering in the woods and wilds of Australia, evidently gave a new accession of vital stamina to my frame. It is said that the climate of Australia makes young men old, and old men young. I do not believe the first part of the proverb, but I am quite certain that there is a great deal in the second part of it. During those two years I chiefly lived in a tent, and led a quiet, free, and pleasant life in the open forests and wild country, continually shifting our scene as we took the fancy, now encamping in some valley among the mountains, now by some pleasant lake or river. In fact, pic-nicing from day to day, and month to month, watching, I and my two sons, with ever new interest, all the varied life of beast, bird, and insect, and the equally varied world of trees, shrubs, and flowers. My mind was lying fallow, as it regarded my usual literary pursuits, but actually engaged with a thousand things of novel interest, both among men in the Gold Diggings, and among other creatures and phenomena around me. In this climate I and my little party enjoyed, on the whole, excellent health, though we often walked or worked for days and weeks under a sun frequently, at noon, reaching from one hundred to one hundred and fifty degrees of Fahrenheit; waded through rivers breast high, because there were no bridges, and slept occasionally under the forest trees. There, at nearly sixty years of age, I dug for gold for weeks together, and my little company discovered a fine gold field which continues one to this day. These two years of bush life, with other journeys on the Australian Continent, and in Tasmania, and the voyages out and back, gave a world of new vigor that has been serving me ever since. During the last summer in Switzerland, Mrs. Howitt and myself, at the respective ages of sixty-eight and seventy-six, climbed mountains of from three to five thousand feet above the level of the sea, and descended the same day with more ease than many a young person of the modern school could do.

As to our daily mode of life, little need be said. We keep early hours, prefer to dine at noon, are always employed in "books, or work, or healthful play;" have no particular rules about eating and drinking, except the general ones of having simple and good food, and drinking little wine. We have always been temperance people, but never pledged, being averse to thraldom of any kind, taking, both in food and drink, what seemed to do us good. At home, we drink, for the most part, water, with a glass of wine occasionally. On the Continent, we take the light wines of the country where we happen to be, with water, because they suit us; if they did not, we should eschew them. In fact, our great rule is to use what proves salutary, without regard to any theories, conceits, or speculations of hygienic economy; and, in our case, this following of common sense has answered extremely well.

At the same time it is true that many eminent men, and especially eminent lawyers, who in their early days worked immensely hard, studied through many long nights, and caroused, some of them, deeply through others, yet attained to a good old age, as Lords Eldon, Scott, Brougham, Campbell, Lyndhurst, and others. To what are we to attribute this longevity under the circumstances? No doubt to iron constitutions derived from their parentage, and then to the recuperative effect of those half-yearly flights into the Egypt of the country, which make an essential part of English life. To a thorough change of hours, habits, and atmosphere in these seasons of villeggiatura. To vigorous athletic country sports and practices, hunting, shooting, fishing, riding, boating, yachting, traversing moors and mountains after black-cock, grouse, salmon, trout and deer. To long walks at sea-side resorts, and to that love of continental travel so strong in both your countrymen and women, and ours.

These are the saving causes in the lives of such men. Who knows how long they would have lived had they not inflicted on themselves, more or less, the destroying ones. There is an old story among us of two very old men being brought up on a trial where the evidence of "the oldest inhabitant" was required. The Judge asked the first who came up what had been the habits of his life. He replied, "Very regular, my lord; I have always been sober, and kept good hours." Upon which the Judge dilated in high terms of praise on the benefit of regular life. When the second old man appeared, the Judge put the same question, and received the answer, "Very regular, my lord; I have never gone to bed sober these forty years." Whereupon his lordship exclaimed, "Ha! I see how it is. English men, like English oak, wet or dry, last for ever."

I am not of his lordship's opinion; but seeing the great longevity of many of our most eminent lawyers, and some of whom in early life seemed disposed to live fast rather than long, I am more than ever confirmed in my opinion of the vitalizing influences of temperance, good air, and daily activity, which, with the benefits of change and travel, can so far in after life save those whom no original force of constitution could have saved from the effects of jollity, or of gigantic efforts of study in early life. For one' of such hard livers, or hard brain-workers who have escaped by the periodical resort to healthful usages, how many thousands have been "cut off in the midst of their days?" A lady once meeting me in Highgate, where I then lived, asked me if I could recommend her a good doctor. I told her that I could recommend her three. She observed that one would be enough; but I assured her that she would find these three more economical and efficient than any individual Galen that I could think of. Their names were, "Temperance, Early Hours, and Daily Exercise." That they were the only ones that I had employed for years, or meant to employ. Soon after, a gentleman wrote to me respecting these "Three Doctors," and put them in print. Anon, they were made the subject of one of the "Ipswich Tracts;" and on a visit, a few years ago, to the Continent, I found this tract translated into French, and the title-page enriched with the name of a French physician, as the author. So much the better. If the name of the French physician can recommend "The Three Doctors" to the population of France, I am so much the more obliged.

May 20, 1871. Hygiene of the Brain, New York, 1878.