and the kidney, and the elongated and pyra- tain circumstances, both methods may be midal shape assumed by the inflammatory more or less combined. Thus, in the same processes when extending through the cortex kidney we might have the virus entering both are, as has been shown, strongly suggestive of by the uriniferous tubules and the lymphatic a ..b. FIG. 9. the virus being carried to and disseminated through the organ by the lymphatic vessels. vessels, and this I believe to have been more or less present in Case 4, in which the inflamI have thus, I think, rendered it clear that matory change was very severe, and the there are two quite distinct ways in which colonies of organisms exceptionally large. In multiple miliary abscesses may originate in discussing miliary suppuration of the kidney, I the kidney, as the result of primary disease of the lower urinary tract, and, although I have FIG. 11. have not specially referred to the state of acute interstitial nephritis, because, although it may be present, I do not think that it is necessarily so. When it does occur, I believe that the explanation which is given by Mr. Marcus Beck is the true one, and which he expresses as follows: "The pelvis of the kidney, and probably also the straight tubules for a greater or less distance, are filled with putrid urine at some degree of pressure. The contact of this irritating fluid damages the epithelium, and causes its rapid desquamation. The septic matter then passes readily through into the intertubular lymph spaces of the kidney, and excites a diffuse inflammation, which spreads rapidly towards the cortex between the tubules." This is just the explanation of diffuse interstitial inflammation that one would look for-viz., a fluid irritant which readily diffuses itself over the entire organ; but this is very different from what goes on in the production of scattered abscesses. Here we have not a fluid, but a particulate and very destructive virus which, from its very nature, cannot diffuse itself in the same rapid way, and so acts described them under two independent head-only on limited areas, but produces greater ings, there can be little doubt that, under cer- destruction. In concluding my remarks on this heading, I would only add that, while many writers have described the straight tubes as the portal of infection, this, so far at least as I am aware, is the first time it has been shown that the lymphatics, quite independently of any other mode of entrance, may form the pathway of the virus from the bladder to the kidney. Large Single or Multiple Abscesses of the Kidney. Cases of this kind form the second division of Class II in my table of classification; and as the general pathology of such conditions is much better understood than that of the cases, the consideration of which has just been completed, it is unnecessary that I should dwell upon them so much in detail. The occurrence of one or more large abscesses in the kidney is a condition very frequently met with in the experience of pathologists, and sometimes also it may happen that the disease has attracted comparatively little attention during life. Numerous examples, too, will be found in all good pathological museums. Roughly speaking, renal abscesses of this kind may be classed under two headings—viz., (1)| where the abscess cavity is formed partly by the pelvis and partly by the renal tissue; and (2) where the abscess cavity is entirely in the substance of the organ. To the former of these the term pyo-nephrosis is often applied, and the general appearances may perhaps be said to be those of a hydro-nephrosis, in which the watery fluid is replaced by pus, that is to say, besides the obstruction to the free escape of urine necessary to set up a hydro-nephrosis, there is in addition the presence of an irritant capable of exciting purulent inflammation, e.g., a calculus. The interior of the cavity is lined with pus; the renal tissue is generally more or less atrophied, and often distinctly loculated, from the suppurative process having encroached upon it more extensively at some points than at others. Abscesses of the second kind, namely, occurring in the substance of the kidney, may be either single or multiple; and, with regard to their general appearance, nothing very special requires to be said. Their dimensions are very variable-often in the same kidney cavities varying in size from that of a pea to that of a walnut or larger being observed. The cavities often contain calculi, and frequently almost no renal tissue is left. The abscesses may or may not communicate with the ureter, and, when they do not, they frequently discharge by rupturing into it. In the later stages the organ generally becomes considerably diminished in size, consisting merely of a series of cavities, in which the original pus, from partial drying in, may have been converted into caseous or pultaceous material. Passing now to the subject of the causation of these conditions, a word or two must now be said under each of the headings mentioned in the table of classification. The presence of calculi is one of the most fruitful sources of this larger variety of renal abscess. The questions relating to the intimate pathology and etiology of the occurrence of renal calculi I need not pause to consider, as I am simply dealing with one of the effects of their presence. However, it is to be noted that a renal calculus may form in one of two situations, and, according to its site, may give rise to one or other of the two varieties of abscess just described. It may originate in the uriniferous tubules, when, if an abscess forms at all, it will occur in the substance of the kidney, and may or may not communicate with the ureter. If, on the contrary, the calculus forms in the calyces or pelvis of the kidney, then pyo-nephrosis may be one of the results of its presence. The rationale of the formation of abscess from this cause simply depends upon the well known pathological fact that suppuration is likely to ensue as one of several results of the impaction of a foreign body in the tissues. But it must be remembered that the presence of renal calculus is not always associated with the production of abscess. Calculi are frequently passed; and, even if the stone remains in situ, there is no essential reason why abscess should result, for, as has been shown by several writers, a calculus, just like any other foreign body in the tissues, may become encapsuled by connective tissue and cease to give further trouble. It has also been pointed out that injury may be the starting point of large renal abscesses, and, on general principles, it is quite conceivable how this should be so. A much more important consideration, however, is as to the relationship which injury may bear to the starting point of some cases of renal calculus. Mr. Henry Earle relates a number of cases of renal calculus accompanied by abscess, and shows that in some of them the beginnings of the symptoms could be distinctly traced to injury. In this way, then, injury, if not primarily, at least secondarily, may be the cause of a good many of the larger suppurations of the kidney. A very rare cause of renal suppuration is the impaction in the pelvis of foreign bodies other than calculi. It must only be very exceptionally that such a condition can occur, but that it is possible is proved by the following case, which occurred to myself, in which a bristle was found impacted in the pelvis. The specimen was obtained from the body of a man who had been admitted to the surgical wards of the Western Infirmary, suffering from fracture of this is generally a slow process, and often accompanied by evidences of more or less obstruction to the free escape of urine. The ureter is, as a rule, very greatly dilated, and its internal surface is covered with ulcers. When the ulcerative process reaches the pelvis suppuration of the kidney begins-very often as a pyo-nephrosis-one essential feature in this, however, as in all suppurative affections of the kidney, being the presence of an infective virus or irritant. SPECIFIC SUPPURATIONS OF THE KIDNEY. Class III includes those cases in which the suppurative inflammation of the kidney may be regarded as specific in origin, e.g., renal phthisis. The anatomical and other characters of this group of affections are so well known, and have been so carefully described by many writers, that it is quite unnecessary for me to dwell upon them. Briefly speaking, tubercular disease of the kidney may occur in two forms. It may exist as part of a general tuberculosis, or it may occur as a local affection limited to the organs themselves (renal phthisis). the skull, and who died shortly after his ad- may undergo cure before leading to very exmission, so that no history throwing any light tensive destruction of tissue. With regard to upon the condition at present under considera- extensive suppuration of the kidney originating tion was obtained. The organs generally in the second way, it may be remarked that presented healthy characters; but upon proceeding to make a section through the right kidney, a large quantity of pure yellow pus made its escape. Upon laying open the organ, the pus was found to have been collected in a series of large cavities, chiefly in the upper part of the organ, and lying in the long diameter of the pelvis was observed a long black bristle, or wire-like looking body, about 11⁄2 in. long. That this had not accidentally (i.e., during the course of the examination) obtained its position in situ was at once proved by the fact that its lower extremity passed right through, and was immovably fixed in, a branched phosphatic calculus which had been deposited round about it. The branches of this calculus passed into the calyces in its neighborhood. The foreign body lay exactly in the direction assumed by a probe when passed up the ureter into the pelvis. The bladder contained a little purulent urine, but was healthy, as was also the right ureter, which was dissected out in its whole length. A small portion snipped off the foreign body showed it was not metallic. It must first have obtained entrance to the bladder, and then made its way up the ureter to the pelvis of the kidney. The last cause of this form of renal abscess which falls to be considered is old-standing disease of the lower urinary passages. In such cases the kidneys are generally found to be converted into a series of large ragged abscess cavities, and often this condition will be limited Local tuberculosis of the kidney consists in to one kidney, whilst the opposite one presents the development of a suppurative, or more the disseminated points of suppuration, which strictly speaking a caseous inflammation, leadhave already been described in Cases I, 2 ing to the more or less copious discharge of and 6 of the appendix this limitation to one pus. It may originate in the organs themside was present. This circumstance is very selves, or it may be propagated into them from strongly suggestive of the fact that the forma- the bladder and ureter, or from the generative tion of small disseminated points of suppura-organs. The morbid process generally begins tion precedes in many cases the development in the apices of the pyramids, which present of the larger abscesses. Thus, it will easily the usual appearances of tubercular ulceration, be seen that there are two possible ways in and the disease spreads in upon the organ and which such abscesses may originate—viz., (1) down the ureter by the continual breaking by the virus spreading upwards and causing down of successive crops of fresh tubercles at small disseminated abscesses, which, by en- the margins of the ulcers. It may spread down larging and coalescing, give origin to the larger into the bladder, and up to the kidney of the cavities; and (2) by the suppurative process opposite side, along the corresponding ureter. gradually extending along the interior of the The whole organ may ultimately be converted ureter, and SO involving the kidney by into a large caseous mass, in which no renal continuity. tissue may be discoverable, and which is riddled It is quite unnecessary to say anything more by large irregular cavities with ragged, crumthan has been already said concerning the first bling walls, which sufficiently distinguish it of these methods, except again to draw atten- from a simple pyo-nephrosis. But the char tion to the great importance, from a thera acters of the condition are so well known that peutic point of view, of Dr. Moxon's observa- it is unnecessary to particularise at greater tion that disseminated abscesses of the kidney | length. The former variety scarcely falls within the scope of the present essay, as it simply consists in the development of numerous miliary tubercles scattered through the organ, and presenting the same characters as those met with in other parts. It is never accompanied by suppuration. The only circumstance, however, which does require further notice is that in some quarters there seems to be a doubt as to whether the morbid affection just alluded to is in reality a tubercular affection. Thus Ebstein, after pointing out that the majority of pathologists regard caseous inflammation of the kidney as a tubercular affection, says "Without desiring to deny any positive observations, I must nevertheless insist that in a great number of instances neither of these assumptions proves true." He then passes on to make the following somewhat astonishing statement-"The miliary tubercles that are met with in connection with them (caseous inflammations) are quite accidental." I think that few will now be inclined to agree with Ebstein in these remarks. The characters of the morbid change, and the presence of the tubercles, are of themselves sufficient to prove the real nature of the affection; but if further evidence be wanted, it may be found by a careful search for the tubercular bacillus of Koch. Some time ago I had the opportunity of studying the appearances in a case of miliary tuberculosis of the kidney, and after a very careful search I succeeded in demonstrating the presence of bacilli in the miliary nodules. Quite recently, also, in a case of local renal tuberculosis which, along with Dr. Joseph Coats I had the opportunity of examining, huge colonies of tubercular bacilli were found in great abundance in the caseous matter forming the floors of the ulcers. These facts, then, I think, in the light of the most modern views on the etiology of tubercle, would prove beyond a doubt the true tubercular nature of renal phthisis. The in any neighboring part, continuous with it. In reference to some of these, the facts which have already been described with regard to the lymphatics of the ureter and kidney may often offer a reasonable explanation. The virus may have originated in the bladder, and spread up by means of the lymphatics of the ureter to the capsule of the kidney and its surrounding connective tissue. It may then, set up abscesses in this situation, which tend to limit themselves to the neighborhood of the kidney rather than to extend in upon the organ itself. Thus, a perinephric abscess may originate which apparently has no relationship whatever to any other part. The condition of the capsule of the kidney, which has been described as being present in Case 2, is of importance in this regard; and further, the remarkably loose connective tissue surrounding the kidney offers a very favorable breeding ground for the propagation of infective germs. I do not say that this explanation will suffice for all cases of apparently idiopathic perinephric abscess, but I believe that it will at least explain a certain number of them. APPENDIX. CASE I. See page 54, MED. ABS., 1882. CASE 2. Man, admitted July 7, 1881, in a dying state. It appears that for a lengthened period he had suffered from a scrofulous disease of the testicle, and had some time undergone the operation of castration. At the time of admission was suffering from a severe and long standing cystitis, and in a few days died. The post-mortem by Dr. Joseph Coats: "External appearances present nothing remarkable. Chest. The lungs are adherent at the apices. On section they present very scattered miliary nodules. Posteriorly there is engorgement. Heart normal in size, weighing 11 ounces. The muscular wall of the right ventricle is very thin, and greatly invaded by fat, so that PERINEPHRIC ABSCESS. Class IV. formation of abscess in the tissues surround. ing the kidney may be caused in a large number of ways, e.g., by injury to the loin, by wounds of the kidneys, by the spreading and bursting outwards of the different forms of renal sup-in some places the muscular tissue has almost puration, by suppuration of the pelvic connective tissue spreading to the loin by continuity, &c. In addition, cases may be met with in which no very obvious cause can be made out, and which are attributed to such influences as exposure to cold, &c. From this it will be seen that there are cases which are distinctly secondary, and with regard to which there is but little difficulty in assigning a cause. In reference to the others, however, which may be looked upon as primary or idiopathic, there will often be great difficulty in finding out what has been the starting point. It is in such cases that I think my observations may sometimes be of service in determining the etiology. In such cases the abscess may often appear to be strictly limited to the region of the kidney, without any very distinct relationship to disease or entirely disappeared. The muscular tissue of the left ventricle is of normal thickness and appearance. Abdomen. The urinary bladder is greatly distended with turbid urine, which deposits a thickish pus in the dependent parts. The bladder is exceedingly irregular, its internal surface presenting frequent rough projections. There is no normal mucous membrane remaining. The right ureter is greatly distended, and shows near the kidney a sigmoid flexure. The pelvis is somewhat dilated. In every region of this kidney there are small abscesses in great abundance. These are sometimes in groups, but sometimes isolated. On removing the capsule, many of the abscesses are found partially to involve it, so as to be partially laid open in tearing it off. This kidney is considerably enlarged, weighing 12 ounces. The left ureter is normal. The left groups and single abscesses contain a creamykidney is much reduced in size, and is con-yellow pus, and are surrounded by zones of verted into a set of cysts, filled with pultaceous hyperæmia. These abscesses are mostly material. Towards the pelvis one or two visible on the surface, and on section are seen calculous masses are discovered. As the to extend through the cortex. In addition, microscopic appearances have already been elongated abscesses are occasionally visible in very fully described, it is quite unnecessary the pyramids. The urinary bladder presents a that they should be further referred to. general thickening of the muscular coat. The mucous membrane is also thickened, and pre with here and there a slaty pigmentation. The prostate gland is penetrated by sinuses of a ragged character, around which the tissue is distinctly slaty in color. With regard to the inflammatory formations in this case, the microscope reveals very simi CASE 3. The kidneys in this case were obtained from the body of a man who had suf-sents somewhat minute injection of the vessels, fered from enlarged prostate, with a prominent middle lobe. The bladder was much enlarged, evidently from habitual retention. The kidneys were smaller than usual, and weighed a little over three ounces, but the natural markings were well seen, and the capsule was slightly adherent. All through the renal sub-lar characters to those observed in the examples stance were seen numerous minute abscesses, the largest being somewhat bigger than a pin's head. They are best seen on the surface, and only a very few are opened into on removing the capsule. In this case the microscope shows that the recent acute interstitial inflammation is much more generalised than in the preceding cases, though still distinctly patchy in character, leaving here and there areas of renal tissue but little affected. Here, too, the sections show that the most intense inflammatory action has been in the neighborhood of the capsule, spreading inwards upon the tissue from it. Microorganisms are not abundantly present, but here and there several small colonies are observed in the cortex. In addition to these signs of recent suppurative inflammation there is abundant evidence that, previous to its onset, the organs had long been in a state of cirrhosis. Many of the Malpighian tufts present the most marked sclerosis; those which do not, show considerable thickening of their capsules; and the interstitial tissue generally is much increased. CASE 4. Patient died from the effects of extravasation of urine, but no accurate note of the clinical conditions has been preserved. The following are the notes of the autopsy. There is considerable sloughing of the skin of the penis and anterior wall of the abdomen. The heart is slightly enlarged, weighing 114 ounces, but otherwise is not abnormal. Both lungs present in their lower lobes distinct pneumonic consolidation, but in neither are there any localised metastatic abscesses. The liver is much enlarged, weighing 97 ounces; it presents slight fatty infiltration, but no metastatic abscesses. The spleen is slightly enlarged, weighing 6 ounces. In it there are one or two small petechial spots, but no distinct abscess or infarction. Both kidneys present several groups of abas well as isolated small ones. The scesses, previously described. The inflammation in the kidney is patchy in character, less in some places, more extensive in others, and leaving areas of quite healthy tissue. In this specimen the micro-organisms were more abundantly observed and more beautifully demonstrated than in any of the others. With regard to their mode of access, it is very probable that they have obtained entrance both by the uriniferous tubules and the capsular lymphatics, but evidently much more abundantly by the latter. In all the inflamed areas large colonies of very minute distinctly rod-shaped organisms are observed. See fig. 7. In addition to the colonies organisms are often seen scattered individually, and this is frequently observed between quite healthy uriniferous tubules. The scattered organisms are micrococci. CASE 5. Patient 39 years of age, and was admitted on account of pain over the liver, of 6 months' duration, followed in a fortnight by jaundice. During the residence in hospital the jaundice was very intense, and the liver was enlarged, but without pain. The appetite was bad; there was no vomiting; and the bowels acted regularly. After admission the temperatures were on several occasions high, with formation of acute abscesses. A few days before death the thyroid body enlarged and felt like an abscess. Post-mortem by Dr. Joseph Coats. The left lung was emphysematous; the right lung presented grey or red hepatisation nearly throughout its whole substance, and also oedema. The heart was normal. The liver was much en|larged, weighing 117 ounces, and was the seat of numerous pale tumors. The gall-bladder and ducts were greatly distended, but it was still possible to press bile through the common duct into the duodenum, but the duct was surrounded by tumor tissue. The head of the pancreas was the seat of a hard tumor, which infiltrated its tissue, but did not involve the duodenum. Its duct was also distended. The |