XXIII. Let those who have money, and to whom there exists CHAP. no necessity for increasing their means, visit the inte resting and beautiful parts of their own country. Let Travel. them go abroad, and see what is new in institutions, wonderful in natural phenomena, grand in nature, and worthy of study in art. A long and healthy sea-voyage may convey them, in renewed vigour, to the calm and even climates of Tasmania or New Zealand, or the more bracing air of South Australia. Here let them live on horseback, and enjoy all that is new and exciting in these younger nations of the earth. The extremes of climate are not forbidden them, and a winter in Canada, or a summer in Norway, may lend them new vigour. In the pure and invigorating air of the upper regions of Mexico, Oregon, or Peru, in the exciting atmosphere of the Cape, are to be found, it is said, fresh pleasures to the senses, and stimulants to the nervous and muscular powers, such as must be experienced to be described. But man can bear and even profit by all extremes. The relaxing influence of Grecian or Roman plains, or of Egypt; the fresh, dry, and calm Desert air, the life passed in tents, are spoken of by travellers as giving new vigour, from the healthy tone which is imparted to the nervous and muscular powers. We have all met men who have done much of this-cultivated men, and not mere idlers-wanderers of necessity and of liking, who have fought off the inherited taint, and who have lived to old age, hardy and vigorous, and temperate in all things.' And this, which need not be an altogether selfish existence, but may include many to help and much that is useful to do, is one of the high and pure enjoyments which in certain cases money is permitted to purchase. 6 The outline proposed seems Utopian; but phthisis is the disease of the rich as well as of the poor, and the knowledge of what can be done, and what is suitable, should be possessed by every medical man at the pre CHAP. XXIII. Children of workmen. sent day, when travelling has become almost an institution among us islanders. Where this plan cannot be carried out, let country life be resorted to, and this is within the reach of almost every one, if certain sacrifices be made for it, and it should be remembered that the greatest of sacrifices is health. But what can we say for the victims of the workshop and the garret who are chained to the oar, and who seem condemned to struggle through the worst influences which town life, unwholesome occupations, close dwellings, improper food, imperfect clothing, and other evil agents concentrate upon them? Even here we may say to the parents of a delicate boy or girl, send the child away, where, if there be lower wages, there is pure air, and less inducement to violate physiological laws. This is often possible': the compositor, or stone-mason, or potter, need not bring up his child to the same trade and the same death as himself. Make a farmer, or a butcher, or a dairyman of him, rather than condemn him to an early death. The tendency of the present day is to concentrate all the population in our great cities, where employment is readily obtained, and wages are high. Let us try and set the current the other way, in the case of those whom, by hereditary predisposition, we recognise to be among the threatened. CHAPTER XXIV. PREVENTIVE TREATMENT OF PHTHISIS: OCCUPATION. We have been speaking of the prevention of phthisis in those hereditarily predisposed; and, following the child up to manhood, have endeavoured to point out the influences by which disease is engendered, fostered, and developed into actuality, and by avoiding which we may hope to prevent its access. CHAP. XXIV. The remote cause of phthisis next in importance to Occupation hereditary taint is occupation. There can be no question as to the influence which it has on the production of phthisis. Other diseases equally chronic are undoubtedly not so much caused by it, for the amount of death so induced is more than that of all other chronic affections put together. a remote cause. tion. That which is deleterious in occupations, per se, may be referred to the heads of ventilation, confinement within doors, posture, deleterious matters inhaled, and too great prolongation of working hours. Of Ventilathese, ventilation is probably the most important as influencing the largest numbers; but, if confinement to chambers be added to it, we shall find here the two agents most fertile in the induction of tubercular diseases. The effect of crowding numbers together without sufficient access of air is well known. The extinction of disease by altering the unwholesome conditions in which numbers live is scarcely less striking, although less known. CHAP. Carbonic acid. In their working rooms and sleeping apartments, the lower classes of this and of all other countries are deprived of a sufficiency of air to support vital changes in their integrity. It is not sufficient to measure the exact quantity of carbonic acid which may be present without the extinction of life: a far lower quantity of the impure products of respiration added to the exhalations from the human body, is capable of inducing disease in the system which shall ultimately prove fatal. The respiration of impure air directly debilitates the vital powers, enfeebles the nervous system, depresses appetite, deranges the secretions, and leads to retention of effete matters in the blood. The decarbonisation of the blood is directly lessened by the absence of a sufficient equivalent of oxygen in the respired air, and some have even gone so far as to attribute phthisis directly to this cause. And whether the retention of carbon in the system be a proximate cause of phthisis or not, we shall do well to consider the conditions under which its exhalation from the lungs is increased or diminished. The following facts about carbonic acid demand our attention. * It forms about one-fourth of the whole air exhaled. About 160 grains of carbon are exhaled every hour in a state of health. The exhalation of carbonic acid is increased by cold, diminished by heat: at 96° it is half that exhaled at 32°. It increases after 30 years of age, is stationary after 45, then diminishes. It is greater in males than in females, lessens during the whole menstrual period of life, augments when the catamenia cease. * Dr. M'Cormack, of Belfast, has advocated this view. It is increased if the menstrual function be interrupted, and during pregnancy. It is increased in the robust and muscular (rather than by height, breadth of chest, or weight), by bodily exercise (one-third), by eating, by the exhilarating emotions, during the wakeful state, in the early hours of the day. The opposite conditions to these cause its diminution. It is less in the evening, during bodily repose, and in chronic respiratory diseases, &c. In most of the conditions which seem to retard the exhalation of carbonic acid, we may recognise those which favour the development of phthisis. A feeble, non-muscular male, insufficiently or improperly fed, undergoing the anxieties of providing for the daily wants of himself and others dependent on him, wakeful and at work during night hours, deprived of bodily exercise, shut up in heated apartments, exhibits the conditions in which the exhalation of carbonic acid is lessened; but are not these the same which are known to lead to phthisis? Yet the induction of tubercular disease cannot be wholly due to the retention of unoxygenised carbon in the blood. However much blood changes are retarded and interfered with by it, there are doubtless other agencies necessary before disease is developed into actuality ;but here we are only treating of the more remote causes. CHAP. XXIV. impurities. The presence of atmospheric impurities in respired Other atair, such as the workers in crowded rooms are com- mospheric pelled to subsist on, becomes an additional source of disease. Carbonic acid and the purely animal exhalations, act primarily by displacing their equivalent volumes of oxygen; the first, perhaps, wholly in this manner, but the latter most likely have an influence as direct |