of their tissue, the sixty-two cases in the Table will be found to arrange themselves into four classes.

1st. Those in which there were evident signs of Pneumonia, as evinced either by the diseased condition being confined to one lung, by its having advanced to solidification, or by the co-existence of marks of inflammatory action in the pleuræ or bronchial mucous membrane. These cases are twenty-eight in number, or nearly one-half of the total amount of deaths.

2nd.-Doubtful cases-in which the lungs presented the characters that are common to the first stage of Pneumonia and to passive congestion, without there being any collateral circumstances by which the diagnosis could be more clearly established. These are eleven in number.

3rd.-Cases in which the lungs were found more or less diseased, but not inflamed or congested. These are nine in number.

4th.-Cases in which the lungs were found healthy. These are fourteen in number.*

Thus it will be seen that on examining the lungs of sixty-two individuals who had died from various surgical diseases, operations and injuries, there were found marked evidences of Pneumonia in twenty-eight, or forty-five and one-tenth per cent. of the whole. Of the remainder, it was doubtful in eleven whether the congestion that was met with was of an inflammatory

*It is probable that cadaveric congestion of the lungs may have existed in many of the cases in this class, but as no actual disease was found, they are entered as being healthy.

or passive character. In nine others, the lungs were more or less diseased, being tuberculous in three cases, bronchitic in four, oedematous in one, and gorged with fluid blood in another; and in fourteen cases only, or little less than a quarter of the total amount-22.5 per cent.-were these organs healthy.

Of the twenty-eight cases in which Pneumonia was found, that disease had advanced to its second stage, that of solidification, in seventeen. The lungs, in the eleven remaining instances, exhibiting the pathological characters of the first stage of Pneumonia, together with evidences of bronchitis, or of pleuritis, as shown by the inflamed condition of the bronchial mucous membrane, and by the effusion of recent lymph, or of serum, into the cavities of the pleuræ. There is one remarkable circumstance connected with the form of Pneumonia now under consideration; namely, the relative frequency of the occurrence of the disease in one or other lung, or in both, at the same time. Andral, Chomel, Forbes, and all pathologists, agree that in ordinary sthenic idiopathic Pneumonia, the right lung is most frequently affected, the left next, and, lastly, both organs conjointly. Now, on examining the twenty-eight cases already mentioned, it will be found that the right lung alone was affected but three times, the left lung alone also only three times, and both lungs together,-not, however, to the same degree,-in no less than twenty-two cases. The reason of this remarkable deviation from the VOL. XXVI.

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law, that appears to govern the occurrence of sthenic idiopathic Pneumonia, may be explained by the peculiar nature of the causes that predispose to and excite the congestive variety of the disease.

In two cases only were the upper lobes found inflamed. One of these was that of a child, who died of phthisis, with intercurrent Pneumonia; the other, that of an old woman, who had been operated on for strangulated hernia. In one case there was found lobular hepatization, the subject being a child twelve years of age, who died with phlegmonous erysipelas of the arm.

That form of inflammation of the lungs which occurs as a consequence of surgical operations and injuries is occasionally of a sthenic, but much more frequently of an asthenic or congestive character, corresponding to the variety of the disease that has received, from various authors, the names of putrid, malignant, congestive, erysipelatous, asthenic, typhoid, and hypostatic Pneumonia, and which is not an unusual sequela of continued fever, and of other affections, attended by much debility of the system generally, or by a vitiated condition of the fluids. I am unable to give the precise ratio of the comparative frequency of the occurrence of these two forms of the disease, the sthenic and the congestive; but I can state that the latter is by very much the most common, being found in by far the larger proportion of those who die of Pneumonia in the surgical wards of a hospital; the disease assuming but occasionally an active character, and that only

in the young and robust, in whom the powers of the system have not been lowered by a long residence in a hospital, or by the depressing effects of irritative fever and profuse discharges.

The essential nature of this congestive form of inflammation of the lung that occurs in surgical cases appears to be the same as that of the so-called typhoid Pneumonia, which has been proved by the observations of Dr. C. J. B. Williams, and of Dr. Hudson, to be essentially a Pneumonia, complicated by a superadded passive congestion. The blood, in this disease, stagnates in the lungs, under the influence of certain causes, and a degree of irritation being at the same time set up, some inflammatory action is excited in the already congested part, which, however, is of a passive type, not being characterized by the formation of those secondary products that are the usual consequences of active, sthenic inflammation. This stagnation of the blood in particular organs is attributed by Dr. Williams either to an altered condition of that fluid, or of the affected capillaries, or of both.

On examining the condition of the system induced by the irritative fever, consequent upon operations and injuries, more particularly when the subjects of them have been depressed by profuse discharges, or by the vitiated air of hospitals, and who have thus been rendered peculiarly liable to the occurrence of congestive Pneumonia, we shall find that it very closely resembles that state of depression in which the typhoid form of the disease is apt to supervene.

The anatomical characters of the two forms of Pneumonia are also identical, the lungs being in both cases, in the first stage, of a livid violet, or purple mottled colour, heavy, compact but friable, readily breaking down into a grumous pulp, and scarcely crepitating when pressed upon, but exuding a very considerable quantity of thin, spumous, frothy fluid. When the disease has advanced to the second stage, the tissue of the organ is more dense, but still very friable; it does not crepitate, but sinks in water, and when cut into, the sides of the incision will be found to present a smooth, uniform, black aspect, not mottled, as in the sthenic form of the disease, but presenting those characters that Dr. Williams has described as being peculiar to " Intervesicular" Pneumonia, and which MM. Hourmann and Déchambre have shown to be very common in that variety of the disease which occurs in the aged. On examining the cut surface attentively, we shall find that this smooth, dark aspect, presented by the sides of the incision, is attributable to a highly gorged state of the capillary network of the lungs compressing the air-cells, which are not, as in the sthenic form of the disease, filled with a viscid secretion, but are either empty, or else contain, at most, a thin serous fluid, that appears to have exuded from the surrounding congested and inflamed tissues.

On inquiring into the causes that give rise to congestive Pneumonia, it will be found that, independently of those circumstances that occasion idio