the admirable tables of the mean temperatures, &c., of different places, that are given in that work; and Dr. Hennen's work, and the Reports on the Health of the Army and Navy, supply ample and satisfactory information, as to the sanatory character of the South of Europe, North America, the West Indies, &c. The subject of climate appears to lead very naturally to that of change of air: one of the most important and most useful of remedial agents. man. A man can scarcely be in a state of such perfect health, as not to be benefited by change of air. Indeed, an occasional change of air may be said to be almost necessary to the perfect well-being of every The workman must leave his workshop, the student his library, and the lawyer his office, or, sooner or later, his health will pay the penalty; and this, no matter how great his temperance in eating and drinking, no matter how vigorously and regularly he uses his limbs,-no matter how open, and dry, and free from sources of impurity, may be the air of the place in which he is employed. - The change of air may or may not be so great as to be virtually a change of climate, according to the circumstances or the necessities of the case; and it may or may not involve the removal of an individual from his usual occupations and pursuits for the time,-substituting a comparative relaxation of mind and body, -or at least a change of direction and effort. In the slighter cases of impaired health, the sleeping in the suburbs of the town in which the life is chiefly spent, or even the spending a few hours of detached days in some accessible rural district, at a few miles distance from the dwelling, may suffice to restore the healthy balance of the bodily functions, and maintain the bodily machine in a fit state for its duties; or in cases of somewhat more urgency, or of somewhat more aggravated character, a more decided change of air, for even a few days, once or twice a year, may suffice to adjust or restore the due economy of the system. The degree of the change of air, or the character of the air selected for the purpose, may be by no means adapted, however, to the degree or the nature of the case, and may deserve and require a careful consideration. The degree of the change of air,—the difference of character between the air to which the system has been habituated, and that of the place selected for the temporary abode,-may be too great, or not great enough: it may be so great as to stimulate unduly, or so great as to relax in an unwise degree, or not sufficiently great to exercise any beneficial effect whatever on the nature of the case, further than the change of scene, and the mental stimulus of such change, may necessarily involve. It may generally hold true, that the change should be to a purer or a more stimulating atmosphere in the slighter cases of indisposition, and to a more relaxing air in the more severe cases of illness; but it would be found to be a rule that is subject to a very large number of exceptions. The man labouring under indigestion, that is the effect of sedentary habits and repletion, would be probably injured by a removal to a warmer and moister air than that to which he had been accustomed, but would be benefited by a change to an air colder and drier than his own. The irritable sufferer from dyspepsia, the result of deficiency of proper nourishment, or of powers too languid to convert his food into blood, would probably suffer an aggravation of his ailments by a removal to a colder and drier air, and be restored to health by a change to one warmer and more moist. In proportion to the weakness, the irritability, the sensitiveness to every impression, ought the change to be to an air that is softer and warmer. In pro portion to the strength of the body, the lethargic state of its powers, the dulled condition of its sensations, ought the change to be to an air which is drier and more cold. There are states of highly irritable system, in which almost every kind of food is felt by the stomach, and gives it uneasiness; or in which a little dust floating in a room produces a fit of coughing; or in which breathing a colder air than usual produces the same effect,—the cough being dry and almost tinkling; or in which the gentlest aperient medicine produces pain, and, perhaps, diarrhoea; or in which the most common domestic occurrence vexes and annoys. Any such state will probably derive advantage from a mild, soft air; and would probably be injured by an air of a different kind. There is a state of system in which there are excessive languor and relaxation; in which the stomach, so far from feeling almost any kind of food, is hardly roused into action by spirits or condiments; in which a strong cathartic medicine scarcely produces an uneasy feeling; in which severe domestic trials hardly produce a temporary impression; in which secretion may be free; in which, if there is cough, it is commonly loose and unirritating. Such a case would be probably injured by the relaxing effects of a soft warm air, but derive benefit from an air at once dry and somewhat cold. The degree of the change of air that is required and indicated is of little less importance than the due selection of the kind of air best suited to the nature of the case. In general, likewise, more or less of a marked difference in the character of the air should be considered to be necessary; and the inhabitant of an inland district might advantageously, under most circumstances, have some part of the coast selected for the change of air; or the dweller in a low or flat country, seek some upland, or possibly mountain district; or the inhabitant of an alluvial, or a chalk, or a sandstone, or a mountain-limestone district, might more advantageously remove to a district of a different formation. Nevertheless, this question might be properly made subservient to the more important question-whether the nature of the case indicates a removal to a more relaxing or a more stimulating atmosphere. Change of air, to be of service, should be well timed; and should, if possible, be obtained in an early period of a chronic and lingering disease; and not be deferred longer than can be avoided, in convalescence from active or inflammatory affections. The more impure the air to which the person has been accustomed, the more cautious and deliberative should be the change of air and its degree, but the more imperatively is such change of air called for. The younger the person, the greater the benefit to be derived from a change of air; and the more necessary and advisable is such change usually found to be. It would be generally well, when a man becomes affected with a disturbed state of his digestive or biliary organs, if such state should not speedily yield to a regulated diet, and exercise, and the usual medicaments, that days and weeks should not be consumed, and indeed wasted, in trying this thing or that thing, or trusting to the beneficence of nature, or to the strength of his constitution; but that an early trial should be given of a judicious change of air. It would be generally well, when a man becomes affected with some degree of dyspnoea, cough, and other indications of an irritable state of the respiratory organs, if, as soon as the urgent symptoms had been relieved,—or, better still, if they should not have as yet come on,—the effect of a wisely selected change of air were early and timely tried. How often, in cases of this kind, have delays been proved to have been not only dangerous, but fatal! There is not a fact in the whole range of pathology, that is more pregnant with sound matter for practical reflection than this: that at no time is a man more apt to contract structural disease, than immediately after the subsidence of active disorder, during the debilitated convalescence. A judicious change of air, as a means of accelerating the restora |