In some cases in which mercury has been medicinally employed, either internally or externally, particles of the metal have been found in bone. Fragments of all kinds of instruments by which bones have been wounded, may be left behind in the wound, - as broken points of knives and swords, and bullets which have been shot into a bone. They give rise to tedious inflammation, suppuration, and necrosis, and are often thus loosened and cast out; but sometimes they remain firmly fixed in the bone during the remainder of the life of the individual, surrounded by indurated tissue.

An attempt to determine the characters of the Constitutional Affections of Bone, particularly the Inflammations and Caries, by reference especially to the appearance of the Bone after Maceration.1

It appears to me to be a matter of much interest to determine in what manner the processes of inflammation and suppuration in bone, which arise from constitutional causes, may be distinguished from one another, and how they may at once be recognized by the characters of the preparation alone: inasmuch as the discovery of certain definite types not only makes us better acquainted with the peculiarities of those processes, but may also assist us in distinguishing them on the living, or at least, in clearing up doubtful cases of diseased bone when examined on the dead.

1 Oesterreichische Med. Jahrbiicher, vol. ix. p. 4.

The distinctive marks of these processes, so far as they are stamped upon the bone, are comprised in change in its texture at the diseased spot, in some alteration of its shape, in the form and boundary of the ulcer of the bone and the necrosis, in the condition of the neighboring osseous tissue, - that is, in the different degrees, or total absence of inflammatory reaction, and the quantity and arrangement of its product, etc, - and in the character of the cicatrix. Moreover, although it has only a secondary bearing on our present subject, yet some attention must be paid to the relation which subsists between different constitutional processes and different bones and parts of bones, to their apparent or palpable tendency to affect compact or spongy, broad and flat, or long bones.

In order to render the subject practical, it is necessary to compare as much as possible corresponding bones. This, however, can be carried, out only to a partial extent, inasmuch as several of the processes occur very rarely or not at all, in particular bones; and it is, therefore, the more important to bring together marked examples of the several diseases referred to.

Syphilis, as is well known, most commonly attacks the flat cranial bones, then the tibia and clavicle, and sometimes the sternum, - in general, therefore, bones which are but thinly covered with soft parts, and compact osseous tissue. It makes its appearance as a painful inflammation, which is more severe at some spots than at others. Where it is most severe, it gives rise to a swelling of the bone (tophus), and to an exudation into its interior, which ossifies and produces a local condensation and permanent thickening of the bone; sometimes, but rarely, exudation takes place on the surface also, which soon hardens in the same manner, and unites with the bone. If the bone be diseased throughout, it swells into numerous confluent bosses, which correspond to the several seats of more severe inflammation, and it becomes shapeless, thick, coarse, and heavy.

Or after having effected this metamorphosis, it terminates in caries. Ulceration attacks an indurated bone. Sometimes, especially on the cranium, it spreads over a large extent of the outer table of the bone, while at other times it rather commits its ravages deeply, and, in the skull, often perforates the bone.

In the former case, the destruction of the soft parts discloses a large ulcerating surface, covered with a layer of lardaceous jelly, which is softening and becoming purulent, and beneath which the indurated bone appears rough and uneven, and, as it were, gnawed. If the ulcerative process stop, the layer covering the bone becomes organized into a very delicate cicatrix, and the bone recovers, not with a smooth, but with an uneven nodulated surface, which subsequently becomes somewhat eburnated, but never quite loses its rugged character. If the sutures still exist, their sharp indentations become thick and blunted. These changes may be readily detected on the living patient through the integuments and their cicatrix.

A circumscribed ulcer has the circular or sinuous form of syphilitic ulcers, and swollen thick margins, which in an ulcer that has perforated the cranium, may be rounded off abruptly or bevelled from without inwards.

An ulcer which has occasioned a superficial loss of bone, heals in the same manner as the analogous process in the soft parts; its cicatrix is depressed in the centre, nodulated, and shining. If the bone be destroyed in its whole thickness, the margin of the opening becomes rounded, swelled, and coarse, and here and there somewhat inverted. Perforation from this cause happens in the cranial and nasal bones, and in the palate.

And lastly, if the inflammation end in necrosis, the syphilitic sequestrum, especially if it include the whole thickness of the bone, presents the same characters of induration, thickening, and uneven, gland-like ruggedness of surface.

The most palpable characters of syphilitic bones are the hypertrophy, and especially the density of their tissue, and the absence of deposition of bone upon their surface in any of the known forms of osteophyte. Under minute examination of a section of a very compact syphilitic skull, numerous Haversian canals were discovered lying far apart, and separate groups of unusually large and black corpuscles, from which a great number of rays diverged. In a section of a piece of syphilitic skull which appeared porous externally, but was, in fact very compact, the Haversian canals were found wide, the corpuscles mostly large, and some of them placed at right angles to the canals: in the neighborhood of particular canals the innermost lamella was transparent, and contained a single row of corpuscles, but it was surrounded by a dark stratum interwoven with very numerous corpuscles, which were thickly set with rays. The lamellar system of some of the larger Haversian canals was uncommonly developed (machtig).

A bone which has been indurated by the syphilitic process is unquestionably liable, at a later period, to expansion of its texture. It seems, however, to happen but rarely; I have observed it once in the tibia, but nowhere else, - never in the cranial bones.