From what has been said, it can scarcely be doubted that rigidity is a certain evidence of death. Prior to this there is no indication derivable from changes in the tissues which can be depended upon ; but the flexibility that follows it affords, if possible, still stronger proof of the condition of the body. There is no state with which it can be confounded if we except the interval between spasmodic and true stiffness; but very little cau tion is requisite for avoiding a fallacy of this description.
The next remarkable diange which takes place in the tissues is putrefaction, a process in which the ultimate elements of the body, operated upon by external causes, enter into combinations incompatible with the existence of those proximate principles of which the tex tural molecules are compounded. Some phy siologists conceive that even putrefaction is not a necessary sign of death. Winslow, however, pronounces it " unicum signum ;" and Bruhier expresses a similar opinion. Hal ler"' says that it may commence in a living person, but that death must be very near at hand. He relates of one Vandenhoeck, his bookseller, that when lying in the last stage of a malignant fever, he prophesied his approach ing end, and that he grounded his prediction upon his sense of smell. Orfila, one of the greatest authorities upon this subject, considers the commencement of putrefaction a less un equivocal sign than true rigidity ; his opinion rests upon the fact that he has known persons completely recovered, notwithtsanding the skin was covered with violet spots, which exhaled an infectious odount It is remarkable that so acute an observer should have overlooked what seems a very obvious considemtion, viz. that these violet spots being caused by extra vasated blood, perhaps in a state of decom position, afford no indication that putrefaction has begun in the solids. Sphacelus, though consisting in decomposition, need not be con founded with putrefaction. The latter change begins always, according to the observation of M. Devergie, either upon the abdomen or the thorax, and has the appearance of a large diffused patch of a green colour, which after wards becomes brown. The brown portion is surrounded by a green areola indicating the extension of the process. Into the history of putrefaction we cannot enter, but must refer to the valuable " Exhumations Juridiques" of MM. Orfila and Lesueur, and to some papers by Al. Devergie in the second volume of the Ann. d'Hygiene on the changes in the bodies of persons drowned, and also to a controversy upon the latter subject between this author and M. Orfila, in the fifth and sixth volumes of the same work.t After the decomposition has advanced to a certain stage, but sometimes without any putre faction at all, the tissues, instead of being dissi pated by conversion into liquid and gaseous substances, which is the essential part of the putrefitctive process, may be converted into said matters widely differing from the original molecules. (See ADIPOCERE and Mummr FACTION.) 3. We have lastly to notice a few signs of the reality of death gathered from the external aspect of the body. The appearance of the face has been already described among the signs of the moribund state. We have only to mention in addition, that instead of the paleness or lividity that were present at the tinie of death, a rosy hue may appear upon the cheeks, which has not unfrequently occa sioned a deceitful hope that life was not yet extinct. The cause was very rationally as cribed by Mr. Chevalier to the action of at mospheric air upon the blood accumulated in the capillaries. This phenomenon is more likely to occur when syncope has followed asphyxia. We remember it once very dis tinctly in a person who had died of acute hepatitis, but in whose last hours there had been considerable pulrnonary congestion; it made its appearance on the third day after death. The state of the eyes has been much
insisted upon by some ; particularly their dul ness, the shrinking of the cornea* from the diminution of the aqueous humour, and the viscid mucous secretion which forms what is called the film of death ; but these appearances may be absent in real death, and present be fore life has terminated. Thus the eye is often proininent and glittering after death by carbonic acid, and by hydrocyanic acid.
The iris is generally represented to be in a state of dilatation. Winslosvt paid conside rable attention to it, and states that he gene rally found the pupil of a moderate size, often much contracted but never much dilated. NIThyttI makes the same observation. The fact appears to differ with different animals. Thus in the cat and pigeon the pupil dilates after death, while in the rabbit it contracts.§ Our osvn observations upon the human sub ject incline us to report the pupil a few hours after death as in a state midway between con traction and dilatation. It is difficult to speak with precision upon the point, because that which would be relative contraction in the pupil of one person would be dilatation in another, and vice versa. We have known ob servers confound immobility with dilatation, and to this circumstance we attribute the common statement that the pupil is dilated at and after death. It is evident that if we admit that the contraction and dilatation de pend upon predominant action of the lon gitudinal or of the circular fibres, we ought to expect in the death of the part neither the one condition nor the other ; but as the con tractility of this as of other muscular parts may survive the cessation of the central func tions, either set of fibres may prevail for a time. It must be remembered however that con traction of the iris may depend upon a cause altogether different from contraction of its fibres, viz. congestion of blood in its tissue, which is said to have some analogy to the erectile. M. Renard states that in some ex periments upon dead bodies instituted for the purpose of ascertaining the effects of com pression of the diaphragm upwards by the development of' gas in the abdomen, found that it occasioned " refoulement vers la tete de la portion fluide du sang qui est contenu dans l'oreillette droite, et par suite, repletion, tumefaction des veines du cou, de la face, de rencephale, suinternent, exsudation sereuse ou sanguinolente par les porosites, les extre mites des reseaux capillaires ; quelquefois aussi, par suite de ce reflux dans les reseaux capillaires, resserrement de la pnpille, reple tion; distension, saillie des yeux, qui etaient d' abord ternes et relliches, &c. &c." M. Villermet has described an appearance of the hand which lie considers characteristic of death. Ile says that when dissolution has taken place the fingers are brought together and slightly bent, but that the thumb is co vered by them, being always found in the hollow of the hand directed towards the root of the little finger. The phalanges of the thumb are extended upon one another, but the first is flexed upon the metacarpal bone. Villerme states that he had often noticed this appearance in dead bodies on fields of battle and in hospitals, but that he had never at tached any importance to it as a sign of death, till his attention was directed to its value by M. Breschet. We have often confirmed the truth of Villerme's description by our own observations, particularly in hospital cases, before the bodies have been subjected to the straightening processes of the attendants upon the dead. When the appearance has been wanting, we have had reason to suspect that it had been removed by force.