Chapter III.STRUCTURE OF THE LEPROMA.
The leprous nodes have on section a smooth, white, glistening surface, if they are still sufficiently young. If one examines, microscopically, sections or teased preparations of fresh nodules, one sees little else but cells, with distinct nuclei, usually of the size of a white blood corpuscle, or rather larger. There are also a few larger so-called epithelioid cells, with larger nuclei, and among the cells, fragments of connective tissue and of blood vessels. With a higher power, one sees in the fluid of the preparation small straight rods, which are not destroyed by addition of potash. These are the lepra bacilli, and thus were they first discovered in the year 1871.
If one teases out preparations in osmic acid solution, or soaks a nodule in the solution some hours before teasing, the rods are coloured faint brown, and one finds them lying mostly in the cells (Plate VI, Fig. 1). If one adds water to a fresh preparation, the bacilli move actively; even in the cells swollen up with water, one sees the bacilli moving; and this led us to regard them as movable, although we at the same time indicateda doubt whether the movement was not simply a molecular one; for the movements were equally vigorous in strong osmic acid solution as in water, and on the addition of glycerine or strong solution of albumen to the preparations, the movements ceased. All later observers, with the exception of Unna, regard the bacilli as motionless. We have no ambition to decide this question, because we know no absolutely trustworthy distinction between molecular movement and independent movement of the bacilli.
The older the nodules become, the more large multinuclear cells are found, and in nodules of the skin and cornea one always finds small flat cells with processes, and with oblong nuclei, which we recognise as the connective tissue and corneal cells (Plate VI, Figs. 2and3).
The protoplasm of these cells is clear, while that of the round cells is more or less granular. The nuclei of the latter are also round, and usually very granular; the flat cells are much less stained by carmine than the round cells, and one sees the flat cells lying on connective tissue bundles. The nodules are richly supplied with blood vessels; in the nodules of the skin it cannot be determined whether the vessels are newly formed, or only those already present in the cutis. They are, however, always of embryonic type. One sees very plainly their formation from cells,and in the cornea, indeed, the vesselsmustbe newly formed. Here the vessels penetrate into the cornea before the nodule forms, and round these vessels, penetrating into the cornea, there are always visible collections of cells which are apparently migrated white blood corpuscles (Plate VI, Fig. 4).
One meets also in old nodules, among apparently only unproductive elements, blood vessels surrounded by young cells (Plate VI, Fig. 5). This appears definitely to favour the view that the tumour cells are, at least for the most part, migrated blood corpuscles. These results have been obtained by examination of fresh nodules, and of those hardened in Müller’s fluid. As we have recently, while hardening the nodules in Fleming’s chromic and osmic acid mixture, and staining the sections with hæmatoxylin, been unable as yet to find any mitoses, and further, have found, by bacillary staining of an old section from a corneal node, an appearance likePlate VI, Fig. 7, we must maintain provisionally that in the lepromata the new formations are, at least chiefly, formed by the immigration of white blood corpuscles. As the round cells infiltrate the connective tissue, the fibres are pressed asunder, and form a network closely resembling that of a lymph gland with nuclei in the angles (Plate VI, Fig. 6).
When the nodule softens, which takes place almost always exactly in the middle, it attains a brownish tint, which is due to the transparent softened part. If one divides the softened nodule, the central part has a distinct brown colour, and the constituents of this part readily fall out. If this is examined under a microscope, one sees, almost exclusively, larger or smaller clumps of a brownish colour, and very granular. They are partly elastic, but partly brittle and fragile, so that by pressure on the cover glass they are easily broken up. One often sees clearly that the clumps lieinthe cells, the nucleus and the cell substance being still evident (Plate VII, Fig. 1). Sometimes only one lies in a cell, which then has the appearance of a signet ring, in whose circle the clump lies, but sometimes several lie in one cell. One finds similar clumps in all other organs affected with leprosy, as in the liver, the spleen (Plate VII, Fig. 2), the nerves, lymphatic glands, the testicle and the eyes (Plate VII, Fig. 3, which shows two clumps from the retina). In the nodes of the skin, but particularly in the testicles, one may find them so large that they may even be seen by the naked eye. Both in the small and the larger clumps there are usually vacuoles, not infrequently several. From the cornea we have often got preparations in which the corneal corpuscles are more or less completelyfilled with brown granules (Plate VIII, Fig. 1). One sees here definitely the cell nucleus in the middle of the brown granular material.
We have described these elements as we first observed them in fresh and carmine-stained preparations, in which they stand out very definitely, as the brown masses do not take up the carmine stain. These brown elements, if one knows their characteristic appearance, may very well serve as diagnostic indications for leprous affections, for, according to our experience, one never fails to find them except in very young nodules. Since the discovery and easy recognition of the lepra bacillus, they have indeed lost their value as diagnostic signs, unless one is examining perfectly fresh preparations. Later investigation has proved that these brown clumps are nothing else but collections of lepra bacilli broken down into granules, and they have received from Neisser the well-chosen name of “globi,” as they usually appear in spherical form. Unna declares, in accordance with his view of the position of the lepra bacilli outside the tumour cells in the lymph spaces, that these “globi” are collections of bacilli in the lymph vessels, and that the vacuoles have arisen from the falling out of bacilli in the middle. In particular, Neisser, Touton, and we, ourselves, have opposed this view, in that we have all seen the bacilli definitely in the cells, and have figured themso. In view of the above description of the discovery of bacilli in fresh preparations and of these brown clumps, there can scarcely be any doubt of the position of the bacilli, and of the cellular nature of the brown clumps. Further, it may be noted that in the testicles the “globi” are chiefly in the lumen of the seminal canals, where no lymph vessels exist, and if Unna says of the “globi”[2]that “no one has certainly determined their cellular character,” he must have said this in ignorance of our earlier publications in Norwegian. The above description and the drawings were published by us in 1869 and 1870, in theNordiskt Medicinsk Arkiv.
In connection with the vacuole, we have found in a testicle a “globus” with vacuoles, and in the vacuoles small granules which were recognised as remains of the nuclei (Plate X, Fig. 2). We add to this the picture of a “globus,” or rather a developing “globus,” with two nuclei, from a skin nodule (Plate VIII, Fig. 4). We have seen earlier, however, that the brown clump may lie in the cell without enclosing the nucleus, and also that the nucleus may lie in the middle of the brown mass. Now, if the vacuoles are transformed nuclei, as we believe, then it would be comprehensible that thevacuoles would be absent in many “globi,” and that in others which have developed from multinuclear cells, several vacuoles would be found. That appears, at least, the simplest explanation of their presence. But there are certain very small “globi” with vacuoles, such as are represented inPlate VII, Fig. 2, c, and those small vacuoles can scarcely represent nuclei; small “globi” may however arise, as is evident atxandx1of the same figure, from clumps of bacilli in the cells. The vacuoles of the larger “globi” ofxandx1may indeed possibly represent nuclei, but not the vacuoles inPlate VII, Fig. 2, a-k, nor the vacuole in one of the small “globi” inx1. Possibly the vacuoles are also the result of a specific degeneration, either of the bacilli themselves, or of the cell protoplasm lying in the middle of the group of bacilli, but on this we would rather not express an opinion.
We have repeatedly demonstrated the position of the bacilliinthe cells, and explained them in diagrams, but in many preparations it is impossible to distinguish where the bacilli lie. The best method of definitely noting their position, which we know, appears to be the fixing of small nodes or small pieces of organs in Fleming’s or Müller’s fluid, with subsequent dehydration and hardening in alcohol; sometimes one gets excellent preparations by simply hardening in absolutealcohol. If the preparations are stained with fuchsin, and counter-stained with methyl blue, or still better, stained with gentian violet, decolourised by Gram’s method, and counter-stained with Bismarck brown or with Bismarck brown and eosin, one will never fail to see the bacilli lying definitely in the cells (Plate VI, Fig. 8). Even in such preparations there are many places where one cannot definitely distinguish the position of the bacilli; but as one always finds bacilli in the cells where the preparations are sufficiently clear, we may safely conclude that the bacilli lie everywhereinthe cells. In the connective tissue spaces one often sees bacilli in and round the nuclei of the connective tissue cells (Plate X, Fig. 8), and although the body of the cell is not visible, we may conclude that the bacilli lie in the cell body, and not free in the lymph spaces. We have found in many sections of the blood vessels in a testicle (Plate X, Figs. 5and6), and in a liver (Plate VIII, Fig. 6, andPlate IX, Fig. 1), white blood corpuscles filled with bacilli, and in both cases only slight affection of the organ, and we also observed many bacilli in the endothelium of the vessels, as Touton and Unna have observed in skin nodules where we, we may remark in passing, have never seen them. From these observations we draw the conclusion that these two organs have been infected through the blood. As we do not know themanner and method of the primary infection of the organ, we must devote our attention to the search for discoveries like those described above, and to the localisation of the bacilli in general, in order to form an idea of the method of action of the bacilli.
As we have already noted, we found in the examination of an excised piece of a recent eruption, in a nodular case of leprosy, chiefly, round cells surrounding dilated vessels, and only after long search, a few bacilli. It thus appears not improbable that during the eruption a toxin (which is circulating in the blood), and only a few bacilli, escape from the vessels at various places, or, it may be, only the bacilli, which produce the toxin locally; that further, the toxin causes the emigration of white blood corpuscles, and that the escaped bacilli only after some time slowly increase in number and gradually fill the cells. From the presence of the bacilli in the endothelium of the vessels and in the connective tissue cells, one may speculate that the bacilli are passively forced into them by the blood or lymph pressure; we have certainly found, in the testicle referred to, bacilli free between the red blood corpuscles in the vessels (Plate X, Fig. 7). Such a fresh eruption may remain stationary or slowly develop into a nodule, or it may apparently completely disappear, and only after several years again becomeapparent, it may be during a fresh eruption. We fancy that in these cases a few bacilli are deposited at the time of the first eruption, and that they have needed years to become so much increased that a permanent nodule has finally formed. That the vessels receive lasting injuries from the leprous infection, appears to us to be proved by the following observations. In an epidemic of measles in one of our institutions, we saw in anæsthetic patients the previous leprous spots, which had long disappeared from view, definitely reappear, thehyperæmiaand turgescence being on these places general, so that the earlier spots stood out as well defined, red, and somewhat swollen areas. All this appears to point to the fact that the bacilli increase very, very slowly, and that possibly they also produce a toxin, usually only in small quantities, which causes no particular injury to the organism, since the patients, in spite of numerous nodules, with millions or milliards of bacilli, may remain in pretty good health for years. We may also conjecture that the toxin which is produced, usually only acts immediately around the bacilli, leading to dilatation of the vessels and favouring the migration of white blood corpuscles. Only occasionally does the production of toxin or the multiplication of the bacilli appear to become so vigorous that toxin and bacilli get into the blood and cause an eruption; possibly this is favoured bypeculiar anatomical conditions, for it is very striking with what varied frequency eruptions appear in different patients. That the bacilli in the nodules are all of them dead, as has been assumed, we cannot admit, so long as the nodules still grow. It appears to us preferable to ascribe the character of the disease to the relative benignancy and slight viability of the bacilli, as Unna has already suggested. As we believe, as explained above, that the bacilli lie almost exclusively in the cells, the question arises whether the cells digest the bacilli, or not. As we often find cells with only one or two bacilli, and as we find in most cells balls or clumps of bacilli, we must admit that the bacilli multiply in the cells. In some cells the bacilli remain lying in separate collections, in others they fill the entire cell body, but they never penetrate into the nucleus. Finally, the bacilli break down into small granules, and this breaking down corresponds, according to our view, to a degeneration of the bacilli. Unna and Lütz have indeed stated that this granular appearance of the bacilli is constant, and is a mark of their structure, that they really consist of small rows of cocci, and Unna has therefore described them as coccothrix. This actual (!) structure of the bacilli, however, only becomes evident under the action of free iodine. But we have seen in our preparations, however they were treated,smooth and granular bacillilying close to each other, and we cannot, therefore, corroborate the view of Unna and Lütz.
Neisser first drew attention to clear spaces in the bacilli; these Neisser regards as spores; we regard them as the first sign of breaking down of the bacilli into granules, and for the following reasons. We have made numerous attempts to cultivate the bacilli, and have attained in all our investigations only (the breaking down of the bacilli into) granules, and in examining a piece of a nodule which lay eight days on broth peptone agar, found all the bacilli beset with clear spaces. And as the result has always been the breaking down into granules, we believe we are right in regarding the appearance of these holes as the commencement of degeneration, and that we are not as yet familiar with spores of the lepra bacillus. It appears as if all bacilli in time break down into granules, particularly in the internal organs, where it occurs much earlier than in the skin nodules; whether this is the result of digestion on the part of the cell, we cannot say; but as the bacilli at first multiply in the cells, and the breaking down appears most definitely and freely when the cells are crammed full of bacilli, it is equally possible that it is the result of diminished nutrition, and as they break down more rapidly in the internal organs, it is also possible, indeed probable, that the higher temperature in theseorgans favours this disintegration. As we have unfortunately not been able to cultivate the bacilli, it is at present impossible to form a conclusion. At all events, we regard the transformation into granules as a degeneration, and believe that the bacilli thus altered are dead.
In the skin nodules we have only once found bacilli in the epidermis; this was in a nodule with many fissures in the epithelium, and partly covered with exudation. We have not been able to decide from our preparations whether the bacilli lie in the epithelial cells or onlybetweenthem, possibly enclosed in wandering cells.[3]Touton found bacilli in the epithelium of the sweat glands, and he and Unna in the hair sheaths also; this situation of the bacilli we have never observed with certainty, and it can only be exceptional, and can scarcely give origin to a “constantly flowing bacterial spring,” as Unna suggests. As a rule, no bacilli are found in the epithelium.
Of the presence of bacilli in affections of the eye, it may be said in general that everywhere, where infiltration is present, bacilli are found. In the clouding of the upper part of the cornea describedabove, which we recognise as keratitis punctata, there are found groups of granularly degenerated bacilli close under the epithelium. This we have only once been able to determine on the living by excision of a lamella of the cornea; in this case the affection was, according to our own view, disappearing, because the bacilli were granularly degenerated. This corresponds with the fact that this characteristic affection of the cornea always ultimately disappears; the granules are probably absorbed. We have already stated that blood vessels precede the nodule into the cornea, and that they are surrounded by round cells. Here, as in the middle of the nodule, the corneal corpuscles are found apparently intact or filled with brown granules (Plate VI, Fig. 3, andPlate VIII, Fig. 1). The same is the case in nodules in the iris, in which one finds the stellate cells intact (Plate VIII, Fig. 2). Round cells are also found in the spaces in the cornea near the nuclei of the corneal corpuscles (Plate VIII, Fig. 3). All this appears to us definitely to indicate that at least most of the cells of the growth are migrated white blood corpuscles.
Dr. Boeckmann has introduced, in the treatment of the nodules growing into the cornea, the division of the cornea in front of the nodules; through the scar formed by the healing of the wound, they hardly ever grow. We have seen such a case inwhich, on the one side of the scar, no actual nodules, but only a clouding appeared, and we were later able to examine the eye anatomically. The nodule reached like a rampart close up to the scar, and all its cells were full of bacilli. On that side of the scar in the clouded part of the cornea, there were found only a few scattered cells containing bacilli; no vessels had penetrated the scar, and only a very few cells had succeeded in making their way through. The treatment is therefore a very desirable one in order to preserve the pupil free. We have been able to prepare no bacillary preparations from theretina, as we have not seen the affection since the discovery of the bacilli; the two brown clumps which are figured inPlate VII, Fig. 3, lay in the outer granular layer of the retina.
As already indicated, the testicles are affected with leprosy in all nodular cases. The affection is both inter-tubular and intra-tubular. In a testicle only slightly affected, we found bacilli everywhere in the endothelium of the vessels, and in several dilated vessels white blood corpuscles filled with bacilli (Plate X, Figs. 5and6); and in some places also bacilli lying free between the red blood corpuscles (Plate X, Fig. 7). At the same time, and especially where the affection is more marked, the bacilli penetrate into the seminal canals, and lie grouped in their walls around the nuclei (Plate IX, Figs. 4and5,Plate X, Fig. 1), and their epithelial cells are more or less filled with them (Figs. 1, 2and4).
The bacilli appear rapidly to break down into granules, and one finds, especially in the seminal canals, globi, sometimes enormously large, as if they were formed by the running together of several epithelial cells. We have found here globi where a nucleus and a little protoplasm were evident (Plate X, Fig. 3), and a globus where there lay in the vacuole small fragments stained with Bismarck brown (Plate X, Fig. 2). As it has been proved that a man affected with nodular leprosy may beget children, and as the globi lie in the seminal canals, it is not altogether impossible that these may be thrown off with the spermatic fluid, and that in this way the ovum is infected. But as, according to our view, these globi contain only broken down and degenerated bacilli, it must be regarded as very doubtful whether they are still infective. In examining the contents of the seminal vesicles, we have found in them neither bacilli, nor globi, nor any spermatozoa. It is an old conception that lepers suffer from satyriasis. This is, according to our experience, certainly not the case. The leprous testicle is finally completely destroyed by the scar-like contraction of the connective tissue, and one finds only here and there traces of the seminal canals around the globi which they enclose.
When the liver is severely affected with leprosy, there are evident macroscopically, fine white, or yellow, streaks or points, which shine through the capsule and are more evident on the cut surface (Plate IX, Fig. 2); they evidently lie in the acini. One also finds round cells with bacilli along the portal vessels and in the capsule of Glisson. Here and there we find also scattered bacilli in the acini, and as is evident from a specimen hardened in Fleming’s solution, the bacilli lie in the endothelium of the blood vessels (Plate IX, Fig. 1). In the liver cells we have never seen bacilli, but we have found here also, in the vessels, white blood corpuscles containing bacilli (Plate VIII, Fig. 6, andPlate IX, Fig. 1).
The affection of the spleen may also be recognised macroscopically by the yellow streaks and points in its substance (Plate IX, Fig. 3), but the affection must be pretty severe to be recognised macroscopically; the cut surface is then somewhat dry. The affection has its seat in the arterial sheaths and the Malpighian bodies; and in this organ also one can in good preparations definitely recognise the position of the bacilli in the cells (Plate VIII, Fig. 5).
The glands in the hilum of the liver are, when that organ is affected with leprosy, definitely leprous, and the affection of the glands is often more evident than that of the liver itself. In thehilum of the spleen we have once or twice found leprous lymph glands.
This leprous affection of the glands is macroscopically very readily recognisable. The glands are swollen as a whole, without any alteration in their form. On section, one sees the ampullæ and the medullary cords of a yellow or yellowish brown colour; this colour gives to the glands such a characteristic aspect that they can hardly be mistaken. The affection is best studied on the inguinal glands, and the retro-peritoneal ones in connection with them. The lowest inguinal gland is always most swollen, reaching sometimes to the size of a pigeon’s egg; the ampullæ and trabeculæ are coloured throughout a deep yellow; but the somewhat thickened capsule and the connective tissue framework have retained their greyish semi-transparent appearance, so that the structure of the gland stands out very clearly, especially if the lymph sinuses are injected with blood pigment, which is sometimes the case when there have been peripheral hæmorrhages in the nodules. As we advance upwards the glands are gradually less swollen, and the yellow colouring of the ampullæ and trabeculæ less intense, and one can further follow in the retro-peritoneal glands a gradual diminution of the affection until, about the level of the kidney or rather higher, normal glands are once more met with. The glands arepermeable, but penetration is evidently more difficult, for the lymph vessels leading to them are dilated, especially those of the lowest and most swollen glands.
With great patience and moderate pressure one can succeed in artificially injecting the lymphatics without causing extravasation. It may even be the case that only one, or at most one or two ampullæ are affected. Microscopically the ampullæ and trabeculæ are found more or less filled with brown bodies or globi. These are evidently lymph cells which have become filled with bacilli and their degenerative products—granules.
One could hardly have a better demonstration of the functions of the lymphatic glands, as filters, than in these leprous glands. The circulation through them is not arrested; nevertheless, the glands retain the infectious product, and if it pass one gland it is arrested and retained in the next. Sometimes the quantity of this infection is so small that one or two ampullæ are sufficient to retain the whole of it. This indicates that the circulation in the gland does not take place exclusively through the lymph sinuses, but that the lymph reaching the gland must at once enter the ampullæ. A similar process is seen in tubercular lymphatic glands, in which one often finds only one or one or two ampullæ infiltrated with tubercle.
In the nerves the bacilli are found partly in round cells, which lie around the vessels and between the nerve fibres, and partly in the cells of Schwann’s sheath; here also they break down into granules, and in time completely disappear. The finer details of the affection of the nerves are best studied on the ciliary nerves when the eye is affected, because there one can examine the finest nerves without cutting sections or putting them through any manipulation which might injure them. One often sees the myelin sheath pressed in by bacilli or cells filled with granules (Plate XII, Fig. 2), and one finds nerve fibres without a myelin sheath and with a more or less atrophic axial cylinder (Plate XII, Fig. 1). These drawings clearly explain how the pressure on the axial cylinder at first causes pain, and later, when atrophy has set in, anæsthesia. And one can also understand that when the leprous affection passes off without complications, the axial cylinders are again restored and become functionally active.
But on those places above referred to, where the nerves run superficially over bones or joints, and are exposed to pressure and stretching, secondary inflammation is added to the process.
While the primary leprous affection hardly appreciably thickens the nerves, the secondary inflammation causes a very marked thickening.The ulnar nerve at the elbow may attain a diameter of 7 to 8 mm. or more, and when the secondary inflammation disappears the connective tissue contracts, and the previously thickened nerve becomes thinner than normal. This whole process usually advances very deliberately, and years are required before anæsthesia is developed to its full extent. While the section of the thickened nerve is quite smooth and of a pale brown colour from the numerous globi present, the section of the atrophic nerve, though also smooth, is as pale as the section of a tendon. It consists almost exclusively of connective tissue; every trace of bacilli has disappeared, and one sees hardly a suggestion of nerve fibres. The leprous affection is healed, but only a completely functionless rudiment of the nerve remains.[4]