*

is one of the rarest lesions met with in the lungs, and almost always occupies the base of the organ, whilst tubercular abscess is situated in the apex. The reason why pneumonic abscess so seldom occurs, has been accurately pointed out by Dr. Stokes ;† and a moment's reflection will shew, that it is next to impossible an abscess of this nature could form at the root of the lung.

These circumstances, taken in conjunction with the fact, that true pneumonic abscesses are not accompanied with very copious expectoration; but, on the contrary, are found to contain an exceedingly small quantity of pust, will enable the observer to arrive at a correct diagnosis in a similar instance.

* "At the period when Laennec published his work on Auscultation, purulent collections were found but five or six times in the inflamed lung; they were yet very small. The largest abscess met could scarcely admit the ends of the three fingers joined together. As for ourselves, it has not fallen to our lot more than once to see a real abscess after a pneumonia, at the La Charité.”—Andral's Clinique Medicale, by Spillan, p. 382.

He alludes to another example of abscess of the lung after pneumonia, presented to the Royal Academy of Medicine by M. Honoré. These two appear to be the only cases Andral has met with.-Op. cit. p. 382.

"But it is in the anatomical structure of the lung that we find the true explanation of the point in question. If we compare the viscera, with respect to the liability to form abscess, we find that in those in which the earlier products of the inflammation can be got rid of, there is the least liability to abscess. In the brain, which has no excretory duct, abscess is a common result of inflammation; abscess of the liver is less common than that of the brain, and more so than that of the lung; abscess of the kidney may be placed next in the scale, and that of the lung decidedly the last in the order of frequency. Considering the bronchial tubes as excretory ducts, we must admit, that of all the viscera, the lungs have the most extensive apparatus for excretion, whether we consider it in a vital or mechanical point of view. From the first, the products of irritation are got rid of by expectoration; and even in the suppurative stage, the accumulation of the matter is prevented by the universal permeability of the lung."-Stokes on Diseases of the Chest, p. 313.

"The rare instances, in which what may be regarded as abscess in the lung really takes place, occur when a portion of lung has been consolidated by inflammation, obliterating the air-cells. In such consolidated portions of the lung suppuration may take place, and produce a collection of pus having the character of

VOL. XXV. No. 73.

F

In one of the cases I have detailed, the bronchitic rales were diffused all over the sound lung, and yet no trace of inflammation could be detected at the post mortem examination; in the other, a few mucous rales were heard occasionally at the root of the lung, which disappeared after each fit of coughing, attended with purulent spitting, and were unaccompanied by any fever or distress of breathing which could legitimately be ascribed to bronchitis.

We are therefore warranted in deducing from the foregoing cases the following rule. That purulent expectoration in empyema, though attended by quick pulse, sweating, emaciation, and other hectic symptoms, is not indicative of tubercular or pneumonic abscess, unless accompanied by unequivocal physical signs of these lesions; but, on the contrary, it is to be regarded as the consequence of an effort of the constitution to get rid of a large collection of purulent matter, by one of the ordinary emunctories.

Since the above was written, Dr. Stokes has informed me of the particulars of two cases, in both of which there were extensive empyema of one side, and copious purulent expectoration, but without any of the usual signs of abscess or chronic bronchitis. These two cases, from a physician of such accurate observation, strengthen, in an essential degree, the position upon which the diagnosis, above announced, is grounded, and confirm the conclusions to which I have been led.

Andral also details the particulars of a case of empyema, in which, before death, purulent expectoration took place, "which seemed to come from a tuberculous mass;" but at the post mortem examination no cavity was detected in either lung, some crude tubercles were found in the upper portion of the right one. In his remarks on the case, he says, we shall also

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abscess. The pus so formed is neither very pure nor very copious. I do not know that I have seen above a drachm collected in such a cavity, and in most of the instances which I can call to mind, there was also present, gangrene of the lung, which had produced some slough or eschar."-Hodgkin's Lectures on the Morbid Anatomy of the Serous and Mucous Membranes, vol. ii. p. 5.

direct attention to the nature of the expectoration, similar to that yielded by large tubercular cavities, and which was merely the product of the bronchial mucous membrane." The mucous membrane presented no trace of disease.*

CONDITION OF THE SOUND LUNG IN EMPYEMA.

There is, however, a true bronchitis of the sound lung which occurs in empyema, where the lung of the affected side is so compressed and bound down by adhesions as to be unable to take any part in the respiratory process. In four cases which I have witnessed, the disease was ushered in by accession of fever and increased difficulty of breathing, and no satisfactory cause could be assigned, save the additional duty imposed on one lung by the useless state of the other. In these instances the expectoration was not purulent, nor did it differ in any respect from what usually attends acute bronchitis, and in all, the affection disappeared on an amendment taking place in the opposite side of the chest.

Such cases are not likely to be confounded with those in which the mucous and gurgling rales are produced by the quantities of pus in the tubes, the result of vicarious secretion. But there is also another condition of the sound lung in empyema, which, though it has escaped the notice of writers, it is necesssary we should be familiar with, inasmuch as our overlooking it, or, on the other hand, attaching too much importance to it, will lead us into error, namely, congestion of the mucous membrane, producing physical signs of bronchitis, or some of the stethoscopic signs of pneumonia. This is by no means an unusual complication of empyema. I have observed it now in several instances, and have no doubt that many cases, presenting the physical signs denoting these conditions of the sound lung, have been recorded as examples of empyema of one side, with bronchitis or pneumonia of the opposite. A little attention will enable us to distinguish this state very readily from an

* Vide Clinique Medicale, by Spillan, p. 566.

acute bronchitis, or a pneumonia, supervening in the sound lung during the progress of the empyema, for though we may discover bronchitic rales all over the back part of the sound lung, in which the respiratory murmur had previously been puerile and free from rale; or we may often hear a loud, large, and loose crepitus (such as is commonly heard in typhoid pneumonia) yet we do not find the dulness on percussion, and characteristic sputa of pneumonia on the one hand, nor, on the other, the increase of fever, exacerbation of cough, or great difficulty of breathing which almost invariably accompany an accession of bronchial inflammation. On the contrary, neither the general symptoms, nor the feelings, nor the appearance of the patient indicate the supervention of a new disease. I am disposed, therefore, to attach very great importance to the absence of these latter symptoms as diagnostic signs between this affection of the lung and true bronchitis, for considerable experience and close observation of thoracic disease have convinced me of the truth of the doctrine long since advanced by my friend and respected preceptor, Dr. Stokes, that these symptoms are a measure of the irritation, rather than of the obstruction in the lung.

It is unnecessary to point out the errors in treatment and prognosis, into which a neglect of the means of distinguishing between these complications of empyema, will lead the practitioner; the patient will be harassed by cupping, blistering, and other local applications, and his apprehensions awakened, and the alarm of his friends excited, by the intelligence that his sound lung has become engaged, for we all know how fondly both patients and their friends look forward to a recovery so long as only one lung is diseased, and the error is not confined merely to those imperfectly acquainted with auscultation, it is daily committed by many, otherwise very familiar with the science.

There is no difficulty in accounting for congestion of the sound lung in empyema, if we reflect for a moment on the following circumstances, which I have long considered as quite

explanatory of the phenomenon. First. It occurs for the most part in those cases, where, from some unusual cause, the patient cannot lie on the affected side, but prefers reposing either on the sound side, on the back, or assumes the position termed by Andral diagonal decubitus, or, as more frequently happens, he lies altogether on the diseased side. In any of these situations, it is evident that congestion in particular parts of the lung is favoured by the position of the patient. Secondly. A still more importantand efficient cause is owing to the circumstance that in consequence of the compressed, collapsed, and impermeable condition of one lung, the whole quantity of the blood circulating through the body, is driven into the sound lung for aeration and oxygenation, and its sojourn in that lung is prolonged beyond the period which in health is necessary for the purification of only half the quantity; and, as a natural consequence, congestion from this cause depends on the greater or less degree of permeability enjoyed by the lung of the affected side. The disappearance of this condition of the lung is one of the first symptoms which indicate the absorption of the pleuritic effusion, and proceeds in direct ratio with the gradually increasing expansibility of the compressed lung.

CONDITION OF THE LIVER IN EMPYEMA.

In connexion with this subject I may be permitted to allude to the condition of the liver in empyema. For the most ample and accurate observations we possses respecting that organ in the affection under consideration we are indebted to the researches of Dr. Stokes ; but, besides the observations detailed in his celebrated work, there are many points worthy of attention, which have hitherto been left uninvestigated.

It is generally supposed that the only way in which the liver is engaged in this disease, occurs when an extensive empyema of the right side depresses it mechanically; its condition in empyema of the left side has been altogether overlooked. Some time ago I met with a case in which an effusion into the left