There are instances in which death has taken place very suddenly (chloroform, lightning, blow on epigastrium), and the blood remains liquid in the cardiac cavities and shows no tendency to coagulation (Walshe). The intimate cause of this condition is difficult to state, although the sudden shock to the nervous system is doubtless the main explanation. Under these circumstances the lining membrane of the heart is apt to become stained with the coloring matter of the blood.66 At times the ventricles of the heart contain no blood at the autopsy. This is more frequently true of the left than of the right ventricle. Even then the auricles are more or less full.
66 Bristowe, in Reynolds's System of Medicine, vol. v. p. 106.
II. Terminal Clots.—These clots are found at a period more or less removed from the time of death. It may be that they have been present in the heart many days before the fatal termination is reached, or indeed that the act of dying, when the whole organism is overcome by the numerous conditions which inevitably tend in this direction, is mainly instrumental in their rapid production. Of course their outward aspect as well as their intimate structure will vary greatly with their age and with the disease which has been present. Never are they formed entirely of cruor; frequently they are composed of a large quantity of fibrin. Their coloration varies with the quantity of red globules, leucocytes, and serum shut up in the meshes of the latter. In the cruoric as well as the fibrinous clots time also works changes of coloration. In the latter by the mere expression of the fibrin the coagula become less shiny and take on a darker tint, and when deeply colored by red globules they may go through many changes of tint from a violet or red-brick color to a pink. Usually, however, these latter changes require a much longer time to be effected than is properly understood in the term terminal clot. The latter is white, with a yellow or green tint, or again of a fleshy color with spots of deeper hue upon their surface. These are nothing more than small masses of blood, although to superficial inspection they may appear vascular. In structure they may be homogeneous throughout, but this is extremely rare, for in the same clot we habitually find different parts which are evidently of different ages; and not only is this true, but what leads more to confusion in regard to the precise age of a given clot is the fact that a relatively old one is at times juxtaposed or intimately annexed to a purely cadaveric one. To make the distinction of what portion of clot has been formed some time, and what part in the agony, is occasionally almost impossible. Owing to the manner of death or to certain rapid chemical changes which may take place, the interior of terminal clots is at times softened and filled with a puriform material which is probably only softened fibrin.67 These clots are more or less firm and elastic. They adhere quite intimately by a number of roots to the walls of the heart, and are twined around the chordæ tendineæ, the musculi pectinati, and are closely attached after this manner in the depressions between the columnæ carneæ. Sometimes they send off long projections into the large vessels which proceed from the base of the heart. These latter may be cylindrical in form and fill up the vascular calibre, or appear like so many flattened and ribbon-like strips. The elasticity of these clots is made especially evident when we attempt to tear them away from the cavities in which they are adherent. They come away in small pieces, and show a rough, irregular surface where they have been torn asunder. Upon pressure the terminal clots allow a smaller or larger amount of serum to exude from their surface, according to their age and the site of their formation. If the quantity be large, the clot is much reduced in size and changes considerably its physical characters. It must be evident, therefore, that if a clot be contained in the ventricle, and be submitted for any notable length of time to active and forcible contractions, it cannot contain any large amount of serum. In the auricles near the appendages the clot does not bear any very strong outward pressure—not much more, in fact, than it would in an aneurismal sac. Clots in this situation may have existed, therefore, for quite a time before all or even a great part of their serum has exuded (Legroux). Rarely, terminal clots are somewhat stratified. The form of these clots is variable; usually flat, they may also be globular, ovoid, or thick. As they pass through the cardiac orifices they are narrowed. At a level with the sigmoid valves the full margin of the cusps is marked upon their surface, and discoid masses, formed usually almost exclusively of fibrin, fill the cavities of the cusps and are moulded to their surface. To this condition great importance has been attached as indicating the formation of the coagula prior to death. In fact, Poullet68 has endeavored to prove irrecusably by experiments upon animals that in all cases where these masses were present the clot had been formed quite a length of time during life. Raynaud,69 although admitting the ante-mortem foundation of these imprints, nevertheless holds that they are produced in the act of dying. The author,70 owing to the fact that he has found more than once the amount of fibrin and globules about equally proportioned in the deposits of the sigmoid sacs, considers that they may be formed after death. In this opinion he is upheld by Walshe, who goes even farther, and states that he has seen coagula filling the right ventricle, the infundibulum, pulmonary artery, and its branches, and tightly grasped by all these parts in which this mark was apparent,71 and yet the coagulum was certainly formed post-mortem. This opinion was further sustained by more than one case observed during life, and in which the final symptoms were not at all those usually assigned to cardiac thrombosis. According to Richardson,72 the fact that the clot is grooved upon its surface or contains a canicula through its interior is a positive proof of the passage of the blood-current, and hence of its formation during life.
67 Cycl. of Anatomy and Physiology, p. 114, 1848.
68 Thèse de Montpellier, 1866. In this sign Poullet also endeavored to show a distinguishing feature between clots formed within the heart and those transported from one of the large veins of the extremities and arrested in the heart. Before Poullet, these sigmoid prolongations had been mentioned by Gallard and studied by Chauveau of Lyons and Gardner of Glasgow.
69 Dict. de Méd. et de Chirurgie, vol. viii. pp. 562 and 565.
70 De la Thrombose cardiaque dans la Diphthérie, Paris, 1872.
71 V. (after Walshe) such a specimen, No. 3636 Univ. College Museum, London.
72 On Fibrinous Deposits of the Heart, 1860.
Whilst attaching a certain amount of importance to the signs just mentioned as indicating the age of a clot, Parrot73 is disposed to consider the color, consistence, intimate attachments, and histological structure of far greater importance in determining their formation some time prior to death. Usually speaking, the terminal coagula have gone through no retrogressive changes as regards their primary elements. The red globules are perhaps paler than normal, but the fibrillæ of fibrin are still distinct and the leucocytes show well-defined nuclei and do not contain any fat-granules. These coagula, both terminal and cadaveric, are found more frequently in the right than the left side of the heart (Bouillaud). For the terminal especially the right auricle is a frequent location (Parrot). This does not coincide with the following table, taken from Legroux, and which shows the relative frequency of the products in the different cardiac cavities: In 48 cases concretions were found "in all the cavities at the same time, 8 times; the right cavities and the left ventricle, 2; the left cavities and the right ventricle, 2; the two ventricles, 4; the two right cavities, 5; the two left cavities, 3; the right auricle, 1; the right ventricle, 7; the left auricle 8; the left ventricle, 8 = 48 times."