80 Path. Anat. (Syd. Soc. trans.), vol. iv. p. 217.
81 Dis. of the Heart and Aorta, Part ii. p. 1020.
82 Dis. of the Heart, 4th ed., p. 106 (b).
83 Bristowe, in Reynolds's System of Medicine, vol. v. p. 107.
84 Bull. Soc. anatomique, Feb. 5, 1875.
85 Bristowe, on "Softening Clots in the Heart," Path. Society's Trans., vol. xiv.
It is to the rupture of cysts of similar characters with those just detailed that may be properly ascribed pyæmic symptoms occasioned by the diffusion of their contents in the circulation.86
86 Ogle, loc. cit.
Coloration.—The color of ancient coagula varies from a dull white to that of a grayish, slightly yellowish, or slate tint. These extremes of color and all intermediary shades depend upon the age of the clot, the manner of its formation, the larger or smaller number of red corpuscles shut up in its fibrinous texture, and the chemical transformations it has undergone. In order that the opinion at first formed of the age of a clot by its coloration may be of some value, it is essential that this ocular examination may be further aided by the results of microscopic investigation. Occasionally, as already stated, the ancient coagula are covered by clots of late formation, but these may ordinarily be distinguished by even slight inspection.
Consistence.—Usually the ancient coagula are firm, friable, and without elasticity. They are then readily detached from their insertions by traction, and always come away in small masses. On other occasions they offer considerable cohesion, and preserve their form when we attempt to tear through or break them. The degree of friability is in proportion with the regressive alteration of their substance. Sometimes the clinical history apparently indicates that a heart-clot has remained soft during several years (Walshe). Coagula, however, which have evidently been formed for a considerable period are frequently fibrinous or cartilaginous in their structure, and a deposit of calcareous material in their interior or upon their surface is occasionally found.