INDURATION-MATTER, Coagulable lymph, destined to remain in the condition of induration-matter, becomes more and more opaque and solid, and acquires an imperfect fibrous character (as Mr. Gul liver first showed) from simple condensation of the original fibrillated fibrin, and indepen dently of cell-formation. The fibres become thicker, and run more flexuously, as the consistence increases,— a change probably caused by contraction from removal of ater.
The properties of induration-matter vary greatly. Of greyish, yellowish, or white co lour ; opaque; frag,ile and cheesy in consistence, or firm as fibro-cartilage ; of trifling, or of extreme tenacity ; rarely crisp, and generally distinctly tough ; commonly elastic; in its firm est condition creaking on incision ; occurring in the forms of membranous layers, more or less perfect sacs, nodules, patches (plane, puc kered, cupulated, or convex), points, granules, wart-like bodies, or altogether amorphous ; essentially of protein-basis, yet yielding gela tin in a certain proportion, prone to contain fat (granular or cholesteric), and often becom ing the seat of saline (ossiform) deposits ; induration-matter is perfectly similar to none of the natural textures. As it hardens, its texture densely and closely set, often acquires a chondroid appearance without containing a particle of true cartilage ; it is imperfectly (or not at all) vascular. Microscopically it is found to be unprovided with prolific cells ; nor are the few cells it may contain, nucleated as a general fact. It is rendered pale by acetic acid.
Induration-matter is endowed to a remark able degree with the property of slow con traction,— a property which renders its presence most beneficial or most baneful. It is this property, on the one hand, which in the process of cicatrisation by granulation, reduces within reasonable limits the surface of the largest wounds ; while on the other, it may cause painful deformity, as in the instance of burns, or actually cause death, as in the instance of healing intebtinal ulcers.* Presenting itself wherever vessels exist, and entering non-vascular textures by imbibition ; co-existing with all varieties of textural change, and exercising important influences on local nutrition, induration-matter would require a volume for its full description. We must content ourselves with an enumeration of some of the principal sites in which it occurs. Induration-matter forms : ( A.) On membranous surfaces, where it is known under the names of pseudo-membrane, matter of adhesions, &c. Of the serous class the pleura
is by far its most common seat ; next follows the pericardium ; then the peritonseum ; then appear the tunica vaginalis and synovial mem branes; and longo intervallo the arachnoid.# Among mucous membranes it appears on the respiration-surface in croup, plastic bronch itis, and pneumonia (in all which situations it is not distantly allied to diphtheritic de posit), and on the intestinal surface as in dysentery. It appears on the endocardial and valvular surfaces in the warty and gra nular forms ; in the arteries and veins in the patch-like shape. The so-called glands of Pacchioni illustrate its occurrence on fibrous surfaces (B.) Free in cavities. So it has been occasionally found forming rounded masses in the peritonscal and pleural sacs ; the so-called " loose cartilages" in joints are in the great majority- of instances composed of induration-nnatter ; so too are those small melon-seed-like bodies, producing double saccular distension at the wrist-joint.-1- (C.) In the cellular membrane. The sub-cutansous, (less frequently than the sub-mucous, and still less than the sub-serous) cellular membrane, becomes infiltrated with this material ; in parenchymatous cellular tissue it is singularly common. In addition to the ordinary cases of its occurrence in the latter, as a result of siimple inflammation, it constitutes in great part the substance of the morbid element infiltrating the kidney in certain cases of renal disease attended with persistent albuminuria, urine of low specific gravity, anasarca, &c.; infiltrating the capsule of Glisson, it plays a notable (but not the whole) part in hepatic cirrhosis ; and infiltrating the substance of the lung (especially in certain cases of empyema), it converts that organ more or less completely into a chonclroid mass. Seated in the intra serous fibro-cellular tissue of the cardiac valves and chordm tendineae (where it is associated soinetimes with atherorna) its contractile force produces the puckerings and shortenings so frequently observed. (D.) As imperfect cica trix. Wherever a solution of continuity oc curs, the cicatrix may be formed of this sub= stance ; take the instance of false joints : in some situations cicatrix seems always to be thus constituted, of which more in the next section. (E.) On new surfaces. Induration matter may form on wounded, burned, and ulcerated surfaces; and supply a sac more or less perfect round the cavity caused by abscess, tuberculous softening, and fistulm.