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Spirit of the Eritish and American Periodicals, &c.
(No. 41 of a Decennial Series.)
APRIL 1, TO JULY 1, 1844.
I. ILLUSTRATIONS OF THE THEORY AND PRACTICE OF VENTI
LATION, &c. By David Boswell Reid, M.D. F.R.S.E. Lon
don. 1844. II. THERMAL COMFORT : OR, Popular HINTS FOR Preserva
TION FROM Colds, Coughs, AND CONSUMPTION.
George Lefevre, M.D. Second Edition. London. 1844. We take it that the increased attention which has of late years been paid to both personal and public health is a proof that the medical profession frequently acts in a very disinterested manner. We are continually occupied in lessening the possibility of the occurrence of those very maladies, whose existence is a source of emolument to us. It is quite true, that if medical men banded themselves together for the purpose of preventing the removal of the causes of disease, just as various monopolizing fraternities do for the limitations of the necessaries and luxuries of life, their conduct would be met with the indignation of the public, not because it would be more injurious or destructive to life and happiness than the proceedings of the worthies alluded to, but because its ill-effects, although not greater in extent, would be more obvious in operation. A state of apathy or inaction, however, might have been tenable with little or no reproach, the general feeling with the world at large being that if it is not allowable that a man should use his power in injuring, by impeding the flow of benefits to, others, so is it not to be expected of him that he should go out of his way to benefit them, by injuring his own interests. Medical men take higher ground than this: and we may say, with truth, that the benefit they confer on society, by relieving the various diseases it has become afflicted with, is well nigh equalled by that derived from their counsels for the prevention of their recurrence or propagation. A practitioner is consulted for some ailment, which, perhaps, he is successful in relieving : but what reflecting patient does not perceive the great incidental advantages he has derived from the intercourse he has held with his adviser, whether these relate to a prevention of a return of the same malady, or to general observations upon the preservation of his health or that of No. LXXXI.
other members of his family. So in medical books, a leading feature is always the consideration of the prevention of the diseases they treat of, and that frequently, not by the agency of the class to whom the works are addressed, but by modes too simple to require their aid, and yet not sufficiently obvious until pointed out. In fact, the general tenour of professional feeling has always taken a high moral tone; and has discouraged all attempts at concealment and mystery, even in the treatment of disease, and has encouraged, and often powerfully urged, the adoption of efficient preventive means. Almost every improvement in the sanitary condition of the public has been suggested by the observation and philanthropy of medical men, whose education and opportunities, indeed, furnish them with illustrations of the importance and necessity of change in various practices long before these are perceived by even the observant portion of the public.
There has always been a considerable class of publications dedicated by medical men expressly to furnishing instruction upon the preservation of health; and at no time have these been so prolific, or so well-written, as in our own. Every circumstance of public and personal hygiene has been subjected to long and repeated examinations; and the instructions deduced from these have become now, to a considerable extent, practically useful. The management of health, in every stage of life, has been placed upon a more sure basis, the occurrence of disease rendered less frequent, and, so to speak, less excusable, and its removal more easy and certain. Much remains to be done: but the great point is to rouse public attention to the necessities of the case, and this, we think, has been to a considerable extent accomplished.
Although Dr. Reid's “Illustrations of Ventilation" does not fall exactly within the category of works we have alluded to, and embraces in its ex. position of the exemplifications of the subject, a much wider sphere; yet, it is especially important in the point of view we have mentioned, viz. in calling attention to the evils it would remove, and showing to how much greater extent they prevail than is generally supposed. How far the means here detailed have been successful in the gigantic undertaking of ventilating and warming the Houses of Parliament, or how far the objections bold good to the plans suggested, and, we believe, as yet not very satisfactorily put into operation, for ships, &c. we are not in a condition to offer an opinion; but of the soundness of the principles laid down, of the value of the directions given, and the importance of the exposure of the general defective condition of ventilation among us, we entertain no doubt whatever, and think the public is much indebted to Dr. Reid for the able, and yet easily understood, manner in which he has developed them.
We need not urge upon the medical reader the importance of an abundant supply of pure air. Time was, when this might have been necessary; but the woeful experience of over-crowded hospitals, &c. has produced a complete unanimity of opinion upon this subject among the profession. Some of Dr. Reid's calculations of the aggregate quantity required by large masses of people are interesting. Before quoting these, it may be observed, he considers a much larger quantity of air is required for healthy respiration than many other persons do. Thus, while different observers state two, or four cubic feet of air per minute, to be requisite, Dr. Reid places the quantity, under ordinary circumstances, as high as ten feet.
“ If we look to the fact that less than half a cubic foot of air passes through the lungs of an adult in a minute, this estimate may at first appear excessive : but if we remember that at each expiration, a quantity of air is ernitted which mingles with an additional portion of air largely exceeding its own bulk, and that there are twenty such respirations in a minute, while provision is likewise required for the air that affects the surface of the body, and for the endless variety of minor effects produced by furniture, lighting, heating, refreshments, &c. where no peculiar adaptations for these purposes have been introduced beyond those usually observed, it will be seen that the estimate is by no means immoderate. The real question is not what the constitution can bear, but that amount which is conveniently accessible in ordinary habitations, and which is essential for the wants of the system.”
The following calculations are founded upon the mean of various observations by different experimenters.
“The inhabitants of London, amounting to two millions, respire every minute 370,370 cubic feet, or 124 ton of air, and consequently require for respiration alone 6,653,000 tons per annum. Allowing, however, 10 cubic feet per minute to each individual for the supply of his various wants, the consumption amounts to 359,000,000 tons annually, or nearly 1,000,000 tons daily. They evolve from the lungs about 220,000 tons of carbon, and 215,000 tons of water. In a room 12 feet square, and 12 feet high, containing therefore 1728 cubic feet of air, there are ten persons who respire the whole air in the room in 15} hours, and require a complete change every 17 minutes in order to supply them with the 10 cubic feet per minute.
One man during a life of 50 years makes 525,600,000 respirations, inspires 166.3 tons of air, consumes 18.57 tons of oxygen, discharges 19.8 tons of carbonic acid, containing 5.475 tons of carbon, or about 80 times the weight of his own body (150 lbs).
The inhabitants of the earth, taken at 1,000,000,000, respire annually 3,327,000,000 tons of air, and evolve 1094 million tons of carbon. The total weight of the atmosphere is about, 5,261,000,000,000,000 tons, so that it would require 1,580,000 years to elapse before the whole atmosphere could be respired by the human inhabitants of the earth.
The whole inhabitants of the earth discharge annually from the lungs 107,000,000 tons of water, a quantity which, if collected together, would form a sphere nearly 2000 feet in diameter.” 16.
The quantity of air required varies much under different circumstances. There is a certain amount which, if not furnished, death ensues, but above this there is every gradation until a complete supply is attained, which, in cold weather, is attended with a difficulty and expense that place fresh air amid the luxuries of life. The perception of the impurity of air and the necessity of change becomes blunted by habit, and thus the air of a coal mise, which will not support the combustion of a candle, but only that of a lamp, and which may cause fainting or death to one unaccustomed to it, is breathed by the miners with impunity. So ill-ventilated apartments which produce an oppression of the respiration to one first entering them from a purer air, do not produce this effect upon those who are habituated to them.
Where numbers are crowded together, much air is required, not only for the maintaining the respiration, but also for the sake of diminishing the augmented heat. Air entering a crowded apartment at 60° at the floor,