detached, produce a shower of emboli. At all events, the probability is that the cause of early death from burns and scalds is a primary blood disorder, due to injuries inflicted on the red blood corpuscles by the heat.

Post-mortem appearances. These vary according to the severity of the burns or scalds, and the period of time that elapsed between the receipt of the injury and the occurrence of death. If a burn be caused by radiant heat, it leaves a more or less whitish appearance of the skin. If flame come in actual contact with the skin, the surface is blackened; blisters may be found about the burn. The flame of an explosive gaseous mixture produces scorching and mummification of the skin; coal-mine explosions frequently cause blackening of the skin from coal-dust or small pellets of coal being driven in by the force of the explosion.

Scalds produced by boiling water or steam are accompanied by the formation of blisters, which, however, may be absent at parts where the cuticle has been stripped off. If the scald has been produced by superheated steam, the skin presents a sodden, dirty-white appearance, and blisters may not be present.

After death from burning, the brain and lungs are frequently found considerably shrunk, and the lungs are often of a reddish colour. The heart is generally filled with blood. The mucous membrane of the air-passages is sometimes found injected and covered with froth, and particles of soot may be deposited on it. The kidneys occasionally show signs of nephritis, accompanied by degenerative changes in the epithelium of the glomeruli and convoluted tubes. The mucous membrane of the stomach and intestines is sometimes found reddened, and ulcers of the duodenum are occasionally present, if the patient survived the burn for some time. Although these duodenal ulcers have been frequently seen, yet they are not present in the greater number of cases. The blood is frequently of a bright cherry-red colour, exactly resembling that of blood from a case of carbonic oxide poisoning. In some cases of death from burning, carbonic oxide poisoning is the cause of the fatal event; but even in cases

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where death has not been caused by carbonic oxide, the blood may possess a bright cherry-red colour; under these conditions, the blood gives the ordinary oxyhæmoglobin spectrum, and is readily converted into reduced hæmogoblin by reducing agents. In such cases the bright red colour is attributed by Falk to the reflection of light from microscopic coagula produced from some of the albumin of the blood, the light in consequence only penetrating a superficial layer of the blood, and therefore less of the light being absorbed. According to this explanation, the bright red colour of the blood is not due to any chemical change in its colouring matter, but purely to a physical cause. Bright red blood, the colour of which is due to this physical cause, may be found not only in the bodies of those who have died from burning, but also in bodies which have been exposed to a sufficiently high temperature after death. If, however, the bright red colour of the blood be found to be due to the presence of carbonic oxide hæmoglobin, that is a sure indication of the gas having been inhaled, and therefore of the person, in whose blood it is found, having been alive during the progress of the fire.

Distinction of burns produced before and after death. The important medico-legal question may be raised as to whether the burns on a dead body were produced before or after death. A murderer might, after killing his victim, set fire to the apartment or house, in the hope of escaping detection. If a body be found completely charred, it is impossible to determine whether it was living or dead when first acted upon by the heat; if, however, the burns are less extensive, it may be possible to form an opinion. Such an opinion is mainly based upon the nature of the vesication, and the characters of the contents of blisters that may be found on the body. It was formerly believed that the production of blisters containing fluid only occurred in connection with vesication produced during life; and that blisters produced from a burn after death contained either gases

1 Vierteljahrsschr. f. ger. Med., 1888.

or aqueous vapour, in the latter case being in a shrivelled condition from condensation of the aqueous vapour after withdrawal of the heat. This opinion, however, is now known to be incorrect. It was first discovered that blisters, containing fluid, could be produced on dead bodies affected with general dropsy; and later, it was found that, under suitable conditions, blisters containing fluid may be produced on any dead body. The most important condition is that death should not have occurred too long before their production. Bonchut found

that, by the application of heat, he could produce vesicles containing a watery serum within twenty-four hours after death. If the body be quite cold and rigid, blisters containing gases or aqueous vapour are alone produced. If, however, blisters containing fluid are produced after death, there is a marked difference in the composition of the serum as compared with that contained in blisters produced on the living. In the latter case the serum is rich in albumin, and when coagulated by boiling, or by the addition of strong nitric acid, it sets almost to a solid; in the case of blisters produced on the dead, the serum is almost entirely devoid of albumin, and is only rendered slightly milky by boiling, or by the addition of nitric acid.

Another important method for distinguishing between burns produced before and after death is to look for the presence or absence of marks of inflammatory changes at the circumference of and at the base of each blister. In the case of burns produced on the living there is a deep red line around the burn, and the skin at the base of the blister (after removal of the cuticle) presents a dotted redness, the dots corresponding to the sweat-glands and hair-follicles. In the case of burns produced on the dead, there is no red line around the burn, and the base of the blister is dead-white, unless the burns have been inflicted almost immediately after death. In connection with the redness of the base of a blister, it should be borne in mind that, on the one hand, the redness of the base not uncommonly disappears after death, and, on the other, that a slight redden

ing of the base of a blister occasioned after death may result from exposure to air.

To sum up the distinctions between burns inflicted before and after death :-

I. If the fluid in the blister be rich in albumin, the inference is that the burn was inflicted during life; if containing little or no albumin, that it was produced after death.

II. If the blister be surrounded by a bright red line, the inference is that it was either produced during life or immediately after death, during the molecular life of the part or tissue concerned.

III. If the blood contain a quantity of carbonic oxide, as indicated by spectroscopic examination, the inference is that the individual from whose body the blood was taken was living at the time of first exposure to the burning.

IV. If particles of soot are found in the larynx, trachea, or bronchi, the inference is that respiration occurred after exposure to the fire.

Wounds upon the burned. If wounds are found upon the body of a person supposed to have been burnt to death, it may be a matter of great importance to decide whether the wounds were inflicted before the burning, or whether they were the result of the burning. Injuries are sometimes produced upon the body by extreme heat, which may closely resemble incised wounds; these injuries are mechanical results of the heat, and consist of fissures in the thorax, or abdomen, or in the neighbourhood of large joints, especially at the flexures. These fissures are generally irregular in form and have uneven edges; as the blood-vessels, by virtue of their elasticity, are apt to escape being torn, they may be seen stretching across the fissure. Such a disposal of the blood-vessels is a sure indication of the fissure having been caused by heat, and not by the use of a weapon. Another characteristic that may be found, in

connection with these heat-wounds, is that where the skin has fissured the melted fat has run out of the wound and formed a varnish-like deposit around the fissure. As a rule these heat

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wounds are of no great depth, but cases have been recorded in which they have been sufficiently deep to expose the contents of the thoracic and abdominal cavities. Cases have been recorded in which strangulation marks have been visible on bodies that have been almost charred by burning. No doubt the preservation of such a mark is due to the cord, or other constricting medium, having been left round the neck, and so acting as a protective agent to the skin beneath. In cases of wounds found on partially burned bodies, the possibility of their being due to pieces of timber &c. accidentally falling on the person or body must not be overlooked.

PRETERNATURAL COMBUSTIBILITY OF THE HUMAN BODY (SO-CALLED SPONTANEOUS COMBUSTION)

The term spontaneous combustion' has been applied to two conditions-spontaneous ignitability, and preternatural or increased combustibility. With regard to spontaneous ignitability of the human body, there is no evidence whatever to justify the use of such a term; so that all cases of so-called spontaneous combustion' resolve themselves into cases of increased or excessive combustibility of the human body, it being always understood that burning matter of some kind is necessary to the firing of the human body even when in such a condition of hypercombustibility.

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The subjects of this unusual condition are generally of very intemperate habits and possess flabby, bloated bodies; exceptional cases have occurred among individuals of temperate habits and spare persons. Generally the catastrophe occurs when the person is in a drunken condition, and always when in close proximity to fire or flame of some sort. The association of this condition with alcoholism led to the supposition that the presence of the alcohol in the tissues was the cause of the increased combustibility of the body, but this is not the case. The soaking of dead bodies in alcohol, and the injection of alcohol into the veins of living animals, do not increase the