With regard to disinfectants, it may be well to note that none of the various patent disinfectants are superior to bichloride of mercury, chloride of zinc, sulphate of iron, chlorine, and sulphurous acid; very few are equal to them, and none cost so little. As a gaseous disinfectant for rooms, etc. chlorine is superior to sulphurous acid, but it has the disadvantage of injuring metals, is not so easily applied, and is more costly. It will destroy the vitality of the spores of the bacilli more rapidly and certainly than sulphurous acid, which last, to make sure work, must be exhibited for a much longer period than is customary. I should not feel confident as to the thorough disinfection by sulphurous acid of the hold of an infected ship unless the fumes had been applied for sixty hours. Carbolic acid as ordinarily used is an antiseptic rather than a disinfectant. Its vapor in a sick room is absolutely useless. When applied in strong solution it is effective, for a time at least, but as thus used it is expensive, its odor is unpleasant to many, and masks the odors from putrefying substances and excreta, etc., thus preventing the warning which these odors would give. Its use is in many cases very much like removing the rattle from the rattlesnake.
The suggestions made above for limiting the spread of scarlatina from a case to be treated in the residence of the patient apply—with certain modifications for each form of disease, which will readily suggest themselves to the physician—to all the affections due to portable contagia.
Among the poorer classes, however, it will often be found impossible to obtain the separate room and service and the constant intelligent care which are necessary to ensure the desired result; and in such a case the patient should be removed to a hospital, for his own sake as well as for that of the community. The utility of small hospitals for infectious diseases is by no means generally understood, and very few of our small cities and towns are provided with anything of the sort. If the subject is urged on the authorities of a place, the reply will be that it is an unnecessary expense, that the people would not go to it, and that such an institution is in itself a source of danger. The facts are, that such a hospital costs very little, and is the cheapest insurance against epidemics which a town can have; if it is kept clean and comfortable, the people will use it freely, and if properly managed it does not offer the slightest danger to the vicinity. This question will be further discussed in the last section of this paper.
The principles of isolation as applied to a single case as indicated above may also be applied to infected localities in case of epidemics. When taken in time, all diseases which depend upon particulate contagia for their origin can be stamped out by isolation and disinfection. Unfortunately, to effect this promptly and successfully requires money, labor, and the co-operation of the well in the vicinity; which last it is usually impossible to obtain voluntarily or to compel sufficiently to secure the desired results. A question which sometimes arises in case of epidemics, and with regard to the necessity for which physicians will be consulted, relates to the closure of the public schools. It is certain that the assemblage of children in schools exerts a powerful influence on the spread of such diseases as scarlet fever, diphtheria, and whooping cough. On the other hand, the closure of the schools infringes upon the rights of a large number of the community, and if long continued, as it sometimes must be to be really efficacious, inflicts upon them a permanent loss. It is, moreover, a confession on the part of the authorities of inability to induce or compel what must always be a comparatively small part of the community to take the proper precautions. It is never justifiable to close schools on account of small-pox, and where there is a competent health authority supported by the influence of the medical profession, it must be a very exceptional set of circumstances which justifies their closure for diphtheria or scarlatina.
It is not deemed expedient here to discuss the vexed question of quarantine. It is more important against yellow fever than any other disease, because every day of delay of the entrance of the disease which it secures lessens largely the subsequent mortality, since the duration of the disease is limited by frost. This is not the case with cholera, and the mere keeping this disease out of a place for a few weeks does not diminish its ravages when it has once gained an entrance. To rely altogether on quarantine, either maritime or inland, to keep yellow fever, cholera, or any other disease out of this country is a far greater mistake than to neglect it altogether. The practical way to isolate and quarantine is to get as close to the affected spot as possible. Precautions at Havana for yellow fever, or at Hamburg for cholera, are far more useful to the United States than the same amount of work at our own ports can possibly be; really good work in this direction must be not only national, but international.
XII. MENTAL CAUSES OF DISEASE.—A man may give too much attention to his health and the means for its preservation, and the doing so is both a sign and a cause of disease—probably oftener the former than the latter, except in cases of psychological epidemics. The power of expectant attention, especially if accompanied by belief or fear, to produce derangement of function in the nervous system, and through this to affect the circulatory and digestive systems, is well known to medical men. The effects of an undue amount of brain-work, and especially of the anxiety and worry which often accompany this when it is specially directed to the acquiring of wealth, fame, or power, are also familiar to physicians in our large cities. The analogies between mental and physical exertion are close in some respects, and especially as to the effects of over-exertion in a limited time under the influence of excitement.
The danger from simple mental work, such as study, when there is no excitement from a contest, is small, and depends mainly on lack of physical exercise and consequent disorder of the digestive organs. The risk of producing what Fothergill calls "physiological bankruptcy" is greatest in the youth studying for a prize, the speculator, the man who feels responsibility which he knows he probably cannot meet. The danger of injury from overwork under excitement is a very real one in many of our schools, and, while the evil results are most apparent in girls of the middle and upper classes, the boys and the young men also suffer. The system of pass examinations, in which the standing of the pupil is to be determined, not from the average results of his daily recitations, but from a single examination at the end of the year, produces the greatest risks to health; and this is especially the case where the ambition and pride of the children are stimulated by competition for prizes, medals, etc. Such systems of grading by a single final examination should not be used in ordinary schools, and for some pupils there will always be a risk to health connected with them even when they are of age. No doubt the stimulus of competition is useful with the majority of children as well as of adults, but with some of them it is pretty sure to go too far.
The symptoms produced by undue mental strain are familiar to all physicians, and there is usually little difficulty in tracing the effect to the cause when attention has been directed to the matter; in fact, the patient himself usually knows very well the cause of his troubles. The remedy is, of course, rest—but that does not mean idleness. In speaking of occupation, allusion has been made to the fact that the physician must at times advise his patient as to the adoption of some pursuit, and in cases of this kind such advice is also useful.
The effects of mental strain are often mingled with, and aggravated by, those of stimulants which have been used to spur the flagging energies. Alcohol, tobacco, opium, or coffee used in this way finally increase the very discomforts which at first they relieved.