WAS THE BURN ANTE MORTEM OR POST MORTEM?
In describing the anatomical characters of a burn occurring during life, vesication, the formation of blisters, is regarded as a marked symptom.
While it is not an invariable result in a burn of the living body, it is so constant as to become one of the most important factors in answering the question as to the ante-or post-mortem infliction of the burn. Where the burn has been caused by a scalding fluid, or by burning of the clothing, or the direct application of flame, blisters are more likely to occur than where contact with a highly heated body has taken place. In the formation of a blister the cuticle is raised from the derma or true skin by the effusion of a highly albuminous serum, and the surrounding skin is of a bright or coppery red color. The time of the appearance of such a blister is not fixed. It may occur almost immediately or may not do so for several hours, an interval sufficiently long for death to occur from shock. It must be remembered that a burn inflicted in a condition of great depression of the vital powers with insensibility may be followed by no vesication or redness, but upon reaction and return of sensation both redness and blisters may appear (Case 17). In the absence of blisters, therefore, it cannot be decided that for this reason the burn was post mortem. If from a blister formed on the living body the cuticle be carefully removed, the site of the blister will present an intensely reddened base. In the dead body, if the cuticle be removed, no red base appears, but the surface of the blister becomes dry and of a grayish color.
On the other hand, if the presence of blisters is noted, can it be concluded that the burn was ante mortem? While their presence affords reason for an affirmative answer, careful examination of the blisters as to their character and contents must be made in order to decide; the presence of apparent blisters is not alone sufficient (Cases 20, 18; Plate II.).
Elaborate experiments have been made in order to decide the possibility of producing blisters post mortem.
Leuret,[711] in experiments upon dropsical subjects twenty-four hours after death, shows the possibility of raising a blister post-mortem, but one which can be distinguished from one of ante-mortem production, in that it contains a reddish serum very slightly albuminous. He urges extreme care in deciding this question.
Christison[712] found it impossible to produce a blister a few hours after death. In a patient unconscious from narcotic poison, heat applied four hours before death produced a blister and a red line was formed around the burns. In the burns produced half an hour after death, in the same patient, blisters formed in two places only, and these were covered by dry skin and contained air. No redness appeared around them.
Champouillon[713] agrees with Leuret in his conclusions, from experiments upon dropsical subjects.
Kosack[714] considers blisters with albuminous contents diagnostic of burns during life, but states the necessity for care in deciding in the absence of other signs of reaction.
Wright[715] was able to produce blisters three and a half hours after death containing a small quantity of pale serum. On the same body, similar experiments fifteen hours after death produced blisters containing no serum.
Caspar[716] states, as a result of experiments, that blisters may be produced by flame after death; that they result from vaporization of the fluid beneath the cuticle by the heat employed; that they are not found to contain serum and no line of redness is found at their base. The presence after death of vesications containing serum and surrounded by a reddish base is an evidence that the burn was inflicted ante mortem. He distinctly says: “It is quite impossible to confound a burn inflicted during life with one inflicted after death.”
Woodman and Tidy,[717] in an extended series of experiments, conclude that while blisters can be produced post mortem, they are readily distinguished from those formed ante mortem in containing no serum; and even in dropsical subjects, where blisters containing some fluid were formed, the presence of but a mere trace of albumin was shown; and, in all, no redness about the base of the blisters was produced, nor any appearance of redness after removal of the cuticle.
Taylor[718] has never observed vesications in post-mortem experiments on infants. He cites a case of drowning where the person, “pulseless and apparently dead,” was imprudently placed in a hot bath. Blisters containing bloody serum were formed over several portions of the body. He concludes that hot water on the living and recently dead body, so far as vesication is concerned, produces similar effects.
In experiments on the dead body immediately after death the writer has failed to produce any blister containing serum or fluid. The so-called blisters are produced by the rapid expansion and evaporation of the fluid beneath the cuticle over the portion to which the heat was applied, and differ distinctly from blisters caused during life, in the absence of serum or any redness of adjacent or subjacent parts (Plate II.).
Chambert[719] concludes that in living bodies and in dead bodies within twenty-four hours after death blisters can be produced, and that less heat will develop them in the living. He specially emphasizes the difference, in the albuminous character of the contents, of a blister formed ante mortem and of one formed post mortem.
Jastrowitz[720] emphasizes the difference between blisters formed during life and those occurring in œdematous conditions.
Blisters are to be distinguished from the bullæ arising from putrefaction. There is little danger of confounding such cases. In conditions of putrefaction no redness or line of demarcation exists, and the green discoloration and other conditions of the skin will suffice to establish the diagnosis.
Schjerning[721] considers blisters containing highly albuminous serum as diagnostic of burns produced during life. In some conditions of depression of nutrition blisters occasionally form, but are not liable to be confounded with those caused by burning.
A second anatomical feature of much importance, even more so than vesication, is the condition of the skin to which the heat was applied. It assumes a dusky red color and a dry and parchment-like condition (Case 8). Surrounding this is an area of grayish-white skin bounded by a sharply defined and deeply injected red line, which in turn shades into the color of the surrounding skin. These features are more or less pronounced according to the degree of heat applied and to the length of time of contact; or, in other words, to the depth and severity of the burn (Plate I.).