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fact, the off-hand way in which it is ordinarily practised, would deem it to be; we shall find, indeed, that the observation—i.e. the true and accurate appreciation—of the phenomena of percussion, must be an art of even more difficult attainment than that of auscultation. In percussion, the physician has two distinct facts to deal with, namely, 1st, the production of sound; and 2d, its acceptance by the senses. In auscultation, beyond the simple mechanical operation of adjusting duly the ear or the stethoscope to the part investigated, the observer is concerned only with the second ot these fact* namely, the acceptance of the sound by which he seeks to judge ot the condition of internal organs. The sound requires no art of his to produce it, it is there already, all he has to do is to seize upon it; and as it presents itself, to describe its characters.

Not so is it with percussion, for here, the sound heard, and whkli is to be reasoned upon and judged of, has to be produced by the observer himself; and we think we may fairly object to our textbooks in general, that they have not laid sufficient stress upon this particular item. It is, truly, one thing to rap the chest, and another to elicit that sound which faithfully represents (as far as percussion permits) the condition of its internal organs, and which essentially belongs to the part percussed. Writers have not sufficiently brought to the attention of the student the complicated nature of the agencies concerned in the production of percussion sounds, nor enforced strongly enough the extreme caution requisite in the practice of the art. The manual part of it requires considerable practice and must be dexterous, to be of use ;1 and when this is well performed, and the true effect produced, that true effect has still to be seized upon by the ear, and correctly seized upon; how difficult this is, may be gathered from the fact so continually witnessed, of the different effects the same percussion sound produces on the ears of different individuals, and from this also, that we ourselves have frequently occasion while examining a patient, to modify the opinion, which wo had formed the minute before, of the nature of a percussion sound.

Perfectly true it may be, that there is little danger of even an unskilful observer mistaking the nature of percussion sounds when they present extreme characters; a full and clear sound is known

1 Notwithstanding prejudice against its use, we maintain that the percussionhammer, which Dr Hughes Bennett has so often forced upon the attention of medical men in this country, is a most valuable aid in the performance of percussion. It would be too long for us to state all its merits here, and this ha been already done ; all we can do is to advise objectors to use it, and if af'c: having done so, and given the instrument a fair trial, they still proclaim it * superfluity, we shall be quite contented. Our own conviction of its utility arose in this way: Dr H. Bennett once placed a patient before us for examination in whom the thorax was unyielding ; it required most strong percussionpainful to the patient, and 1 believe still more painful to the operator-:' produce under the left clavicle a Bruit de pbt fele-now here, the gentle* W with the hammer on the plex.meter produced that sound in perfection Tb» fact was decisive—argument was superfluous. ^

t once, and there can be little mistake about the dull leaden lumpy imud of a thorax filled with fluid for instance; but then, let us emember, it is not in these extremes only, that the indications to e derived through percussion, are valuable; we want to catch the isease on its road—raorbis occurrere—to stop it before it has arrived t the stage of injury, which that dull leaden sound indicates; and t is in this very attempt that so many lamentable errors are made, nd chiefly in consequence of the improper appreciation of the facts f percussion which we are now speaking of. Is it, or is it not true, hat simple congestion of the lungs (as Dr Hughes will have it) roduces a change in the percussion sound? Now we must say, as ar as our own experience goes, that most practitioners take the fact i>r certain, and yet let any one search this question, and he will be urprised at the little real grounds there are for belief in such an •pinion! And is it not also true, that physicians for the most part letect a certain degree of dulness over those parts of the lungs vliere, by auscultation, and from general symptoms, they are able

0 surmise the existence of inflammation, even in its first stage 1 >ut the proof has yet to be given, that the percussion sound s duller than natural over a lung not merely highly congested, iut even where a certain amount of effusion has taken place into its issue.

We do not think it necessary to illustrate here at length, what >ve cannot but look upon as the deceptions derived from percussion hrough our faulty method of observation; but we may just refer to

1 most ordinary one: what is more common, for instance, than to iear the physician say " oh! there is no dulness there, beneath that •lavicle," and thence he concludes that the organ beneath is sound; mt can any conclusion be more fatally erroneous'? One would ;hink this is a question—a matter of fact—which might be readily lecided; and indeed it is such, for our best observers from Louis lownwards, have admitted that tubercular matter may be deposited, ind to a considerable amount, within the lung, and yet produce no change, appreciable by the ear at least, in the character of the permission sound, and of the fact also any one may most readily obtain the demonstration by percussing comparatively a healthy lung and i lung through whose tissue tubercular matter is distributed in a certain form and manner. Well, does it not follow from this fact that it is unwarrantable to predict an absence of disease in such a case, because the percussion is natural?

We must confess, that when all the incidental complications of this subject of percussion present themselves to our mind, and when we recollect the little certain knowledge we possess of the principles on which its physical phenomena are founded, we are astonished at the unhesitating conclusions which practitioners draw from its use; how often is it, that they are contented with admitting from it neutral results, which tell no tale, and interfere not with their calculations of the problem they are attempting to solve, i.e. of the nature of the disease they are investigating? No, percussion i? made to speak, and in every case to guide opinions; we have no such word as doubtful in our language of auscultation; we make no allowance for the imperfection of our human organs.

In the present and actual state of our knowledge concerning the physical facts, which give rise to, and are concerned in, the phenomena of percussion, we must not be too minute in our division or multiplication of them; the problem, as we have stated, is a very complicated one, and has never yet been worked out. We may fairly anticipate, indeed, that it can never be displayed with all the precision of mathematical demonstration; the qualities and accidents of sound itself are many; and the particular materials, from which we obtain the phenomena of percussion, for the most part, numerous and ever varying. Consider for a moment the variety of facts included in the term percussion sound; we have to take account of its pitch, its intensity, its duration, and its timbre—phenomena the explanation of which are still obscure.

Again, remember, when we percuss the thorax, we are not beating an homogeneous sounding-board; but that numerous bodies, in health even, ever-varying in their sounding qualities, interfering and obstructing, or strengthening each other in some one or other ol those particular qualities, are the subject-matters of our investigation.

Well, let these positive facts be kept still in view, and we predict that physicians will become more cautious in drawing conclusions as to the condition of internal parts of the human body, and of founding treatment upon such consideration whenever the results of percussion are not clear and manifest, that is, when the sound thereby obtained does not lie somewhere about or near the extremes of that long scale of phenomena which percussion elicits; the perfectly dull sound ot a thorax filled with fluid, and the loud, clear sound of a pleura inflated with air are extreme examples of sounds, and as well-defined as am two most opposing qualities of matter; but mark, as we depart from these distant limits of the scale how soon our difficulties begin, am. how they increase the farther we recede therefrom; we soon arrive at points where we should confess, if we were unprejudiced, that our powers of discrimination fail, where the most delicate ear is unable to appreciate distinctions upon which correct conclusions can be founded.

It is very unfortunate that the terms made use of by authors to express the phenomena of percussion should have no definite general meaning, and that there is no adopted standard by which their exact value may be measured; the liberty of language indulged in by writers leads to much misapprehension on the part of tbek readers. Take, for example, the word tympanitic sound; ask halsa-dozen of the first physicians you meet what they mean by that sound, and you will be surprised" to find how little agreement there is among them, even in such a familiar instance! At one time it* made to represent what its immediate derivation would indicate. viz., a drum-like, full sound; at another, and more frequently, it indicates an amphoric, or metallic-echoing sound, such as is often heard over the stomach and intestines; but how different arc the conclusions to be derived from these different, explanations! perfect health and most advanced disease! Some authors, again (Skoda, for instance), use this term continually, and yet never condescend to explain clearly what they mean by it 1

We have dwelt longer than we had intended on this subject, but t\e have been led on from feeling its importance, and from the hope that our remarks may excite the attention of those who are anxious to enter on a field of observation which will assuredly yield them iinple reward if it be well cultivated.

Dr Weber's work, well translated by Dr Cockle, need not detain is. The first part of it may be said, in short, to be a condensed exposition, and not a good one, of Skoda's views and doctrines on mscultation. The " consonating" theory of bronchophony is adopted, is if it were a fact established beyond all kind of doubt.

We have paid some a.tention to this theory of Skoda, and are jound to say, that there is some doubt whether the phenomenon lescribed by him as such is really consonance of sound at all. The >nly case which appears to demonstrate the fact of the voice gaining ncrease of intensity as it passes through tubes surrounded by conlensed pulmonary tissue, is that most rare one, viz., where the voice s heard louder at some part of the circumference of the thorax than >ver the larynx, i.e., nearer to its origin; but a rare phenomenon n the present obscure state of the subject of auscultation, can urely not justify us in drawing conclusions on which to base the xplanation of an extensive series of facts, which, after all, may be apable of a very different explanation. Skoda's illustrations do lot seem to us to be illustrations of consonance at all.

The second portion of the work is occupied with the organs of irculation; it is very interesting, but not fitted for the student's land, being too physiological and controversial. The opinions of he Germans on this subject will be here found fully discussed.

Dr Davies' book on disease of the lungs and heart has reached

second edition, and its value has already been well acknowledged, t contains a full and clear account of the opinions of Skoda, Zehetneyer, Kiwisch, Hamernyk, and other German authors, on the pecial subjects it treats of; there will also be found in it many oriinal observations of the author. One new chapter has been introuced into this edition, viz., a resume of the morbid anatomy and orresponding physical signs of the diseases of the lungs; upon it )r Davies has evidently bestowed much trouble.

On this chapter we must remark, that we object entirely to such nethod of teaching the meaning of physical signs, and we believe »at there can be no more fertile source of error, than such a manner f dealing with them. If there are no special auscultatory signs


which indicate a given disease, why endeavour to indicate that disease by auscultatory signs? when those signs may be the representatives of half a dozen other diseases; and when we know now frequently it happens, that signs which are usually given as indications of this or that disease, are in reality entirely absent. Dr Da vies, for instance, may tell us, "the physical signs of vomica are those which characterize softening and excavation of the pulmonary substance ;" but let any one turn to his account of the characteristics of "softening anil excavation," and he will soon find into what a bewildering labyrinth Dr Davies has led him. No I we maintain that this teaching of auscultation is radically wrong; of what avail is it, that such and such a disease is represented by such and such signs, when you tell us in the same breath, that the disease may exist, and yet eveiy one of those symptoms be absent; such a defining of diseased processes reminds us of Fuller's definition of inflammation, and, to our idea, is just as ill-fitted to our present state oi knowledge.

Dr Davies' volume, ho\y;ev^^wd\A^T}fie4Msed with much pleasure and profit. It is an gxie^lent exposiuoS/tf the opinions of the German school of au?(©ltation,'*and these opinions have been fairly weighed and considered kff\rtre °1i&'$fcnutj)or's own experience. He, like Dr Weber, adopts Skodas theory of the consonating voice, but we cannot say weV^ffuk^ he proves hiseTlsiz; rather the contrary. He tells us, that a souhi^a^s^wi^es^fiibi^HMance, in a bottle, then only when the columns c^~!MiujQ_tlie-^6ttle are of a given height; when more or less than a certain amount of water is poured into the bottle, the air within does not vibrate in unison with the body sounding without. Now if this be true, and we know it is in every case where consonance occurs, how comes it that the voice consonates on all occasions in bronchial tubes and cavities, when the requisite conditions, as described by Skoda, are present? how comes it, that in every instance, the walls of the tubes being hardened and the tubes themselves free and pervious, that the columns of air within them are just of that exact breadth and length requisite for consonance? This difficulty seems to us unanswerable, and decisively adverse to the general explanation of bronchophony by " consonance. At the same time, consonance may happily sometimes occur, and if so, why not in that rare case referred to above, where the voice is heard louder at some point of the thorax than at the larynx where it springs?

Two papers have lately appeared in the 6th vol. of Virchow's Archiv, by Dr Hoppe, and we cannot forbear speaking of them. M 6 do so, because we believe that the method of criticism and inquiry there followed, is just the very method which will, if properly carried out, lead us to clearer conceptions of the phenomena of auscultation and percussion. We strongly recommend them to the careful consideration of those interested in these subjects.

We cannot conclude without a word upon the little volume which

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