5. The so-called Vegetations or Fibrinous Coagula which occur under the most various forms, more especially when they appear on the valves of the heart, are generally, and without exception, regarded as characteristics of endocarditis. As, however, they are not invariably direct products of an exudative process, but, on the contrary, in some cases wholly, but more frequently only in part, indirect effects of endocarditis, since they undoubtedly also appear independently of that disease, we cannot regard them as signs of endocarditis without some limitation in accordance with what we have already stated, and with that which we purpose advancing in a subsequent part of this work, when we proceed to treat specially of vegetations in the heart.

It follows from the above considerations that the anatomical characteristics of endocarditis are very inconsiderable in number, when compared with those of other inflammatory affections; redness and injection are only seldom to be observed, an inflammatory product on the free surface of the endocardium is not always to be detected, and the vegetations are only conditionally a sign of endocarditis. There remain, therefore, as the only constant signs, opacity and thickening of the endocardium, with the disappearance of the smoothness and polish of its surface. But as these conditions of opacity and thickening of the endocardium may, as we have already remarked, be produced by a process wholly different from that of endocarditis, it will be readily understood how difficult is its diagnosis, and how easily its products may be confounded with those of some wholly different process.

In the above delineation we have purposely limited ourselves to the most important points, in order to give a general sketch of the endo-carditic process; and with the further view of not disturbing our readers by any superficial details, we have described only the characters presented in the most numerous and common cases of endocarditis. We purpose considering this subject with the completeness which its importance demands, and we will then treat of all those points that have been neglected in the present portion of our work. The following observations will contain a notice of many of the more uncommon events occurring in the course of endocarditis, and of many appearances and processes which have merely been briefly indicated in the preceding delineation, together with the terminations, sequelae, etc, of the disease.

a. In intense forms of endocarditis, a separation of continuity of the structure affected by the inflammation not unfrequently manifests itself as a highly important occurrence. It may occur in different ways, either as laceration of a valve, or of one or more of the tendons of the papillary muscles, or of the endocardium on the wall of the heart. This separation of continuity is the final result of a maximum degree of inflammatory loosening of the tissue. The margins of the fissure are generally jagged, and serve as the places of deposit for a large number of vegetations. The tissue of the torn structure, as for instance of a tendon, is usually considerably reddened, infiltrated by inflammatory products, and easily torn. Laceration at the wall may give rise to the formation of aneurism of the heart, whilst, if it affect the valve, it may, under certain circumstances, occasion valvular aneurism.

b. Endocarditis with purulent exudation is not of very uncommon occurrence; and although the recognition of the seat and position of pure pus, as a free product, is, in most cases, impracticable, it is not difficult to prove the extreme probability of the existence of such a process. The loosening of the tissue, the want of polish, and the felt-like character of the endocardium, are very strongly marked in the centre of inflammation, and hence these lacerations frequently occur. In these cases a purulent product mixed with blood is generally found infiltrated into the tissue, if not at the surface of the endocardium, whilst abscesses are occasionally found to have spread themselves over a various extent of surface below the endocardium, in the cellular and adjoining muscular strata, deep in the tendons, and in the tissue of the valves. Finally, the process of suppuration being established, an ulcerous separation of continuity will be effected in various ways, in the endocardium of the walls of the heart, in a tendon, or in a valve. The vegetations deposited on the ulcerated surface and its margins are remarkable for their excessive number, their inconsiderable consistence, bad color, and their tendency to purulent disintegration. The secondary processes in the capillary system terminate in purulent solution, whilst the intensity and malignant character of the general symptoms during life lead us to conjecture that some deleterious substance has been taken up into the blood.

c. Endocarditis is probably always an acute disease; it may, however, frequently recur, and at the same spots; but we cannot admit the existence of a chronic form of the disease, unless, according to Bouil-laud's incorrect view, we regard as such the symptoms manifested during life by its products, and the further development and metamorphosis of those products, that is to say, the terminations and sequelae of endocarditis as given below.

1. Exudations On The Free Surface Of The Endocardium

Exudations On The Free Surface Of The Endocardium in the form of agglutinated, whitish, or bluish-white laminae of different size and form, resembling in appearance a serous or fibro-serous membrane, under which the endocardium appears normal, or scarcely at all opaque. They at one time appear in the form of narrow stripes, at another in that of more considerable, irregular plaques or patches, varying from the size of a silver groschen to that of a zwanzigerstiick [a coin rather larger than a shilling], and admitting of being easily removed from the endocardium, over which they are in general smoothly drawn or occasionally compressed together in folds. They are most frequently observed in the left side of the heart, at the upper part of the septum towards the aortic opening, where they are puckered and drawn aside into plaits by the blood flowing over them. Their texture resembles that of the longitudinal fibrous coat, and they consist in some cases of thick stiff fibres, and in others of soft fibres of areolar tissue. The facility with which the agglutination of the inner milk-spots are severed, and the laceration of texture occasioned by their separation, cause them to differ very widely from other structures. The milk-spots are, however, almost always sharply defined in these cases.

2. Permanent Thichening Of The Endocardium

Permanent Thichening Of The Endocardium and of the Subjacent Tissue becomes the more considerable in proportion to the intensity of the endocarditis, and the frequency of its occurrence at the same spot. It is generally occasioned either by infiltration into the tissue, or by exudation that has solidified and become organized on the free surface of the endocardium; the former of these exerts, however, a preponderating influence, as is especially observed in the valves. Thickening is manifested in the walls of the heart in the form of patches of various extent, in some of the trabeculse as a tendinous ring or sheath, in the papillary muscles as a tendinous covering over their extremities, in the tendons themselves as a wad-like or spindle-shaped thickening, and in the valves as a more or less uniform thickening of their free margins, extending from thence to various distances, and even across the valve towards their margin of insertion. The diseased tissue appears opaque, thick, tough, and of a white color, inclining to yellow; and it is with difficulty that the free exudation and the tissue infiltrated by solidified products of inflammation, which constitute the principal elements of the morbid mass, can be torn or split asunder, both having coalesced, and presenting a single fibroid and compressed texture.

The thickening of the tissue of the wall of the heart is often made more apparent in endocarditis by the association of inflammation of the contiguous stratum of muscle to various depths, which gradually passes into induration, and leaves a fibroid callus in the place of the muscular fibres.

3. Coalescence

Coalescence is frequently associated with this thickening of the tissue. As the thickened tissues coalesce with the free exudation, so also the latter may occasion a fusion of various tissues. In this manner the trabecule enclosed in tendinous sheaths unite with one another or with the walls of the heart, while the same process may be observed amongst the separate points of a papillary muscle, or the tendons of a papillary muscle may merge into either one or several strings, or the different valves may coalesce with one another, or with the wall of the heart or of the vessel.

4. This fibroid mass of exudation exhibits here, as in other places, a marked tendency to shrivel, by which means a shrivelling or shortening of the thickened structure takes place. To this class belong shortening of the papillary tendons, and a shrivelling of the valves associated with various malformations. The wall of the heart is either very indistinctly or not at all shrivelled, since it is raised by the substratum of muscle in those cases where the latter has retained its normal texture and function; the adventitious product is expanded rather than shrunk, owing to the great influx of blood in those cases in which the muscular substance of the heart has been reduced to a state of paralysis by the action of inflammation, or has suffered a change of texture.

5. Calcareous Concretions

Calcareous Concretions become developed sooner or later in the fibroid secondary product, and appear in rare cases in the form of nodular uneven laminae in the thickened endocardium of the wall of the heart, and more frequently as simple nodular or ramified strings or rows, or even as amorphous masses of various thickness in the tissue of the thickened valves, and of the thickened papillary tendons which are generally fused and blended together.

6. We have already fully considered the subject of endocarditis terminating in Suppuration.

d. Although endocarditis is generally characterized by the terminations and sequelae already indicated, the cases in which it terminates by a perfect cure are not of very rare occurrence, as we learn from careful observations on the living subject, and by a correct interpretation of the appearances presented after death. This favorable termination depends occasionally on a complete resolution; or, in other words, on the absorption of the products of inflammation deposited in the tissue, and on the fact that the portion of the free exudation which is solidified on the endocardium, and the vegetations that may be present, are gradually taken up and mixed with the mass of the blood in the form of firiely-divided molecules. In some cases fragments which, from their size and position, do not constitute an impediment to the circulation, may remain; or, again, in other cases partial thickening of the valves is counteracted and rendered inoccuous by their becoming attenuated at one or more points, by a shortening of one or more of the papillary tendons, or an elongation of the muscle or of the extremity of the diseased valve.