SPECTATOR'S LIBRARY.

"Parmozzar, - Vies,: or the Statics of the Human Chest, Animal Hest, and Determinations of Blood to the Head. By Julius Jeffreys. F.R.S.. formerly of the Medical Staff in

India. &e. Highley. Free ow, The Scottish Heiress; a Novel. In three volumes Newby.

'POETRY.

Judas; a Tragic Mystery. By Digby P. Starkey, A.M. Longman and Cu.; Curry, Dalin

MR. JEFFREYS' STATICS OF THE HUMAN CHEST.

THIS volume consists of three parts : the first treating of the quantity and condition of the air in the lungs, and the probable mode of its purifying . the blood ; the second investigates the -generation of animal heat, with a view to show that the vital powers exercise an influence over this process, according to the character of the climate, or at least that in a hot climate the production of heat is much less than under intense cold, even should the consumption of food be similar; the third part incul- cates rather a new rule to English notions—" keep the head warm .and the feet cool." The principle of the recointnendation is this : if a part of a heated body be exposed to the air, the heat will pass off more rapidly in the uncovered than the covered parts ; in the human body, generating a supply of heat, these parts will, by long habit, cause an increased circulation of blood to themselves to keep up the requisite degree of anitnal warmth ; full examples of which may be seen in the red arms of milk-maids, and the red faces of guards, coachmen, &c. The practical conclusion which Mr. JEFFREYS deduces from this .principle is. that apoplexy, in England, is stimulated rather than diminished by generally keeping the head cool, and by the baldness of elderly gentlemen. The hint which set him to work upon the subject was derived from the care with which the hot-dirtied Ilindoos swaddle up the head, leaving the legs and feet un- covered; and among them determinations of blood to the brain are very rare. And the practice he recommends, with requisite care and under proper conditions, is for persons of a certain age, whose hair is getting thin and whose tendency is apoplectic, to wear wigs, shoes, and silk stockings.

The facts which Mr. JEFFREYS urges in support of his theories are not new ; and perhaps something like his views may partly be found in other writers. They are, however, presented by him in so complete and systematic a form, that they seem entitled to the praise of origi- nality; especially the first and last sectians—for the second part, on thegetieration of heat, is neither very intelligibly nor convincingly treated, though the conclusion may be sound enough. Of his three prelections, however, the first, on the Statics of the Chest, is the most curious and important ; and if the practical conclusions to which the theory tends are not so readily put in practice as the di- rections to elderly gentlemen, they affect a much greater number of persons, inasmuch as consumption is more common than apoplexy. Every one knows that without breath we cannot live ; and now- a-days most readers know that by the act of respiration the venous blood is changed into arterial, the dark blood giving out carbon and receiving oxygen. The popular and even the professional notion as to this process, if the bulk of persons have any definite idea upon such subjects, is, that the atmospheric air drawn into the lungs immediately comes into direct contact with the vessels and air- cells. This is the conclusion which Mr. JEFFREYS denies ; and he substitutes a view which we will endeavour to explain, as succinctly as we can.

There are, or may be, in the chest of every one in tolerable health, four distinct portions of air, which our author classes as follows, with the average contents of each part as deduced by himself from a comparison of his own observations with the elaborate experi- ments of other writers.

AVERAGr CO-TESTS IN CUBIC INCURS.

1. Residual air; which, owing to muscular formation, cannot he expelled from the chest by any act of ex- piration, and which remains in the body after death 120

2. Supplementary air ; which is generally resident, but can he expelled by a strong effort, and whose depart-

ure with life is the act of expiring 130 3. The breath; or air continually inspired and expired 26

4. amplemen fury air; ordinwily absent, but which can

be inspired by a strong effort 100

From these facts it follows, that instead of fresh air being con- stantly drawn into the lungs, and stale or carbonized air exhaled, there is always, permanently in the chest, nearly five times as much air as we breathe in, and generally nearly ten times as much. However opposed to the popular notion of the modus operandi of respiration this may be, says Mr. JEFFREYS, it is so, and there is an end of the matter. But he also puts forward a series of argu- ments to show the probability that it should be so, without regard to the fact of its being so, and the objects which Nature has had in view in making it so, as well as an exposition of the manner in which the fresh atmospheric air, after gradual dilution, eventually reaches the air-cells of the lungs. The arguments on this last point, however, are rather conjectural than experimental, and have no very general interest. The reasoning on the two first paints rests more upon facts.and observations, and is also of a more at- tractive kind, as showing the careful provision of Nature. Here are some anatomical facts, whence Mr. JEFFREYS deduces a strong ri priori probability that the pure atmospheric air was never in-

tended to come into immediate contact with the more delicate parts of the lungs.

" But sonic will say, by such an arrangement the air-cella would never be visited by air of the freshness requisite for duly oxydating the blood. The reply to this is, tint, whatever may be our preconceived notions respecting the presence of fresh air in the cells, the statics of the case render it impossible it should ever be there under ordinary circumstances. They assure us, beyond the possibility of a doubt, that it is resident air only which moves into and out of the cells in the action of the cheat. It is this resident air which performs all the duty of (Expiating the blood, and which receives from the blood its eli• minuted carbonic acid and watery vapour. The air of respiration performs no direct duty in connexion with the blood. In its fresh state it does not come even near to the cells ; its duty is altogether indirect; its action is to ventilate the chest gradually, from above downwards, and to receive the impurities gra- dually brought up from below, exchanged for an equal bulk of more recent air,

conveyed, in the manner described. from above. * * • " Such being t he fact, we may discern in it a beautiful provision, offering an answer to the other portion of the question, why should such impure air be always resident in the lungs ?

"Is the following not a very satisfactory reply? As we proceed from the larger air-tubes onwards through their numerous ramifications, till we are lost in searching out the delicate cells, do we not find the pulmonary membrane lining the way, commencing comparatively thick and tough, and getting finer and finer, until at last it becomes too delicate to be clearly discovered, a mere film, overspread by equally delicate blood-vessels? Again, though the greater part of the business of oxydating the blood appears to be carried on in the cells, we are not to suppose that the extensive surface of membrane expanded over the lengthened and infinitely numerous tubes leading to the cells is un- employed. Such a view does not accord with the economy of means every- where discernible in the body ; and it is opposed to the observed development of the blood-vessels, which travel along with the tubes, and spread their minute branches over them, in the same way as, at the extremity of their course, they do over the cells.

" There can be no doubt, that in tubes where the pulmonary membrane grows thin enough, there the air begins to penetrate through it, and to art on the blood circulating over such tubes. Let us suppose the action proceeds with due activity at some Liven distance in the lungs, where the pulmouary mem- brane has a certain thickness, and the air in the tubes a certain .percentage, say eighteen. If such a proportion of oxygen acts with due activity through a membrane of such a given thickness, could we refuse assent to the proba- bility, (were it not a fact absolute,) that, as the membrane grew more and more delicate, less and less oxygen should be found in the air, until in the cells the proportion of oxygen should be reduced so far as to guard against injurious activity in the process, where an infinitely delicate membrane only was inter- posed between the air and the minute blood-vessels? Assuredly, if, where the membrane was much thicker, the process went on with due activity, its activity would become far above what was due, when the membrane became of extreme tenuity, unless the quantity of oxygen in the air fell in proportion, unless the air became as it were diluted in proportion." The reader who is interested enough in this question to wish to pursue it, may refer to the volume; but there is a further view advanced by Mr. JEFFREYS, which has a practical purpose, though the individuals most requiring its benefit may find some difficulty in reducing it to practice. . By a glance at the little table atieady given, the reader will perceive, that whilst the capacity -of the chest is fourteen times as much as the mere " breath" requires, upwards of one-fourth of this capacity is seldom occupied, and that this vacant space is nearly four times the capacity of that demanded by the air necessary to the act of breathing. Mr. JEFFREYS also states that he has found the quantity of supple- mentary air to differ considerably in different people ; and he infers that it differs in the same individual at different times. From

these facts he proceeds to deduce some important conclusions; . •

all, however, resting upon the principle that high breathing is good breathing—that the more supplementary air a person can retain in his chest, and the more he can employ the space devoted to the complementary air, the more vigorous his breathing and his lungs become. Individuals with a full chest and of active occupations have this naturally ; and persons whose pursuits are favourable to its development acquire it : but Mr. JEFFREYS considers its at- tainment, to some extent, to be in the power of any one, who has, we may say, the time and the will to strive for it. We take some passages bearing upon this important point, rather with a view to call attention to the principle, than to recommend its injudicious pursuit ; which might do more harm than good.

RATIONALE OF RUNNING.

During, exercise, and especially during considerable exertion, we know that the hurried circulation of blood through the lungs calls fur a more copious supply of air. To command a range for a deeper respiration, we must either breathe out some of the resident air, and add the room thus gained to the pre- vious range of the re,piration,—or, retaining in our chests the same qUantity of resident air, we must increase the respiratory range by intruding upon the complemental space. This is no trifling distinction. What is vulgarly termed "being in breath," and its opposite "not in breath," appears mainly to depend upon these differeat modes of increasing our respiration. An unpractised runner, for instance, tries to relieve himself by the former method ; but he soon feels the conse• quence of letting out too much of his resident air, and drawing in too deeply atmospheric air, fully oxygenous, and perhaps also cold. He gets out of breath ; that is, when he wants more air than usual, he cannot take* so much ; a kind of asthmatic spasm prevents him from getting air enough down, although the chest is not really much more than half full. On the other band, by practice he instinctively learns to keep adding air to that alreadj present, and to breathe nearer to the top of his chest. "He can then respire deeply without drawing in the fresh air too suddenly and too far into 'mtgs. Also, by increasing the quantity of resident air, his cells are more fully expanded, there is more surface of action, and the blood-vessels are rendered less tortuous still, by which they adroit, with less distress, of the quickened circulation through them.

MEANS OF BECOMING BROAD-COESTED.

Muscular exertion tends greatly to establish a permanently fuller state of the chest. The extent to which the chief !muscles of the trunk of the body are inserted into, or have their origin from the walls of the chest, is one cause of this. In order that such muscles should act with power, we have to draw in a larger quantity of air than usual; and when we want to make a cod- ssiodteirdabileainefTicitlrrtlia;aiiroinlifttlileng,haesteavIliwe.eviigalitlts, owfutillieacetetsot,ctlhoseerithhse, windgepe . are stiffly supported by this bed of air, like a distended bladder, or air-cushion- In this way, the chest can support a great pressure, and forms a firm basis for the vigorous action of the muscles attached to it. When longer-continued but not so strenuous efforts are made, ns in carryint, a more moderate weight for some distance, and even in active walking without any load, a man still keeps his cheat more than usually distended ; holding the air in for a time ex- ceeding the period of en ordinary breath, and then letting it out to take in a fresh stock of complementary air, (to use the term adopted,) to give stiffness to his chest.

Now this action being frequently repeated, must and does have the effect of establishing a permanently fuller state of the chest. It is, in fact, the ren- dering a person " broad-chested ; " the connexion of which with vigour is too striking to be overlooked even by the uninformed, who do not fail to see the fuller condition of the chest, though without an acquaintance with the manner in which it is brought about, or in which it is advantageous.

In such vigorous persons, then, the supplementary air becomes larger, a por- tion of the complementary apace being added to it, and then ordinary respira- tion takes place on the top of this increased supplementary quantity. That this is true, we may satisfy ourselves by measuring the quantity of air such a person can breathe out, and comparing it with that breathed out by a person of sedentary habits. We shall find that the volume of the air durably resident in the chest is much larger in the former, the comparison being made between two persons of the same bulk.

ERRORS OF SEDENTARY BREATHING.

On the other hand, they whose misfortune it is to lead a sedentary life, and to lean over their work, habituate themselves, by the constant doubling toge- ther of the trunk, to do with a smaller quantity of resident air in their chests than is natural or proper. In them, then, the air of respiration is at once in- troduced to a deeper region of the lungs than it ought. Though it is impos- sible, in any case, to exist with no little resident air in the chest as that the air of the breath should flow unmixed into the air-cells tbemselves,—fur the resi- dual sir which cannot be expelled is bulky enough to dilute it considerably,— yet, when the quantity of resident air is materially reduced, it is plain the air of the breath goes in too far, and proves exciting to tubes too delicate to re• ceive it, on account of its full quantity of oxygen, and also, no doubt, of its temperament and other qualities. The distress which the presence of pure air produces in tubes intended to receive only mixed air, leads such persons to accustom themselves to do with less breath than is natural. It is quite an error to think that their chests, at the time, will not contain more breath en account of the position ; fur if they were to breathe out still more of the resident air, they might leave more room for breath than the volume of the breath ever requires, and yet keep their chests within the confined limits they bad been reduced to. The truth of this may be noticed whenever a medical man or friend remonstrates with a girl on ac- count of her tight-lacing. One whose folly has nearly reduced her figure to that of an iusect, end whose countenance betrays the state of her lungs, will yk he able to show that her stays are " quite loose," by thrusting her hand between them and her body.. Many a friend is deceived, as well as the self- destroyer, by this demonstration. All it proves is, that there is yet some sup- plerientary air in the lungs, which, breathed out at the moment of the demon- stration, leaves quite enough room for a respiration of full amount to be car- ried on for the time, and even for the stays all the while to he made to appear loose about the chest.

HINTS TO ORATORS.

The collateral but very important duty of the chest in speak'ng, especially in oratory, requires the command of both the supplementary and complemen- tary spaces. The duration of an act of expiration is greatly increased in giving expression to a long sentence. The chest has to be nearly filled with air: the air, occupying almost the whole of the complementary space, is first spoken forth,Then that of the region of the breath; and in a long sentence, forcibly uttered, a large demand is also made upon the supplementary air. But for this long range, there could be no powerful eloquence. At the same time, a loud voice and long sentences make so frequent and large demands on the sup- plementary stock, as to subject delicate portions of the pulmonary membrane to the-frequent presence of undiluted air, alainst which the supplementary air was especially provided as their natural protection. Bence these efforts either by degrees inure such delicate parts as are visited by the inhaled air to its action,—or, as too frequently happens, the air gains the better of them; irrita- tion is excited ; and, if the efforts are persevered in, disease is established. By employing very short sentences, and by habituating the chest to receive a full complementary quantity of air, that quantity, together with the ordinary region of breath, will be found to suffice; so that the resident air need not ever

be intruded upon. It is of great importance in such cases, that this resident stock should be also of full quantity ; occupying steadily its protective posi- tion ' • there receiving all the impulses of quickly-inhaled breath.; duly modify-

ing the portion of it retained; t nd gradually incorporating it into itself as resi- dent air before conveying. it down into the cells. It is probable, that many a

preacher might continue in his vocation by carefully attending to this simple rule. Indeed many, no doubt, practise it instinctively as a matter of experience, without inquiring into the physiological reason.

There are other curious passages on this subject, especially one relating to the use or injury of wind-instruments ; but we have already trespassed somewhat upon our space, and must again refer the curious to the volume. To any one inclined to practise for a broad chest, we should, however, recommend the simple exer- cises of walking, gentle running, and careful reading aloud, with a

very cautious attempt at lifting weights fully within the muscular power, than any more artificial experiments ; which, till persons have

got the knack of breathing high, would be likely to du them more harm than gocd.