The diagnosis of death from burns cannot be made solely from the external appearances. Blisters which are not filled with serum arise during life. Bright-red blood of charred corpses arises from the direct physical action of the heat and from the production of car bonic-oxide hmmoglobin. The presence of carbon monoxide in the blood is an almost positive proof that the person during life was not exposed to the influ ence of fire. The finding of soot or charred material in the respiratory pas sages is certain evidence that the indi vidual was living and breathing during and in the presence of a fire. Lipkau (Deutsche med.-Zeit., Aug. 13, 1900).
Pathology.—The condition immedi ately following a burn is that of dimin ished blood-supply to the part attacked. This seems in part to be due to the de creased size of the vessels, probably fol lowing a spasm of the vasomotor system. As the blood is prevented entrance into the smaller blood-vessels there is a con sequent engorgement of the viscera, with actual congestion or even inflammation of their mucous linings. The process does not end here, but we note a change in the corpuscular elements of the blood itself; the lumina of the blood-vessels are decreased, which allows the mation of thrombi with more or less complete general stasis and possibly sulting in a cardiac paralysis. This over stimulation of the mucosfe may account for the degenerate changes which have been observed in the abdominal viscera, ending, as stated, in the formation of ulcerations of the duodenum or which have caused the extension of the mation to the colon and terminate in the production of diarrhoea and htemor rhage. Thus the mode of death is parently due in some cases to the forma tion of pulmonary thrombi which oc casion this paralysis of the heart. Other cases probably end in narcotic poisoning from absorption of the dead epithelium or from the burned clothing or other adhered materials.
The gases of the blood diminish markedly. The organism of burned per sons manufactures toxins in large quan tity and of characteristically noxious quality. Roger and Guinard (La Se maine Mad., Nov. 3, '94).
The cause of death from severe burns is intoxication by pathological cleavage products of the body-proteids. which are caused to break up into abnormal and poisonous compounds. Their presence in the urine is of grave prognostic import, for one of the eases did not appear at first to be of great severity, although it terminated in death. S'iginund Fraeukel and Spiegler (Wiener med. Natter, No. a. '97).
Of the theories that have been held as to the cause of death in cases of burns. Sonnenburg's is the most probable: that of a reflex lowering of the vascular tone, with consequent cardiac paralysis; but parenchymatous changes and degenera tions in the kidneys. lungs, brain, etc..
are to be taken into account. Case in which numerous streptococci were found in the blood after death, this showing that burns should be treated with strict. regard for antisepsis. Tschmarke (Cent. f. Chin, July 10. '97).
After examining the blood in ten cases the writer records the following points: The blood flows sluggishly, and is of a peculiar dark, purple appearance. An immediate increase in the number or erythrocytes, in severe, but not fatal. cases, of from 1,000,000 to 2.000,000 per cubic millimetre, takes place within a few hours; in fatal cases. of from 2.000.000 to 4.000.000 per cubic milli metre. A rapidly increasing lencocytosis constantly ocenrs.—in cases ending in recovery often of 30,000 or 40.000 per cubic millimetre; in fatal eases usually above 50.000 per cubic millimetre. Morphological changes in the erythro cytes are slight. The percentage of neutrophiles is 5 omewhat above the normal, but not so much as in the ordinary inflammatory leucocytosis. A considerable destruction of the leuco cytes takes place. especially in very severe burns. Myelocytes may be pres cut in small numbers in severe cases. There is, as a rule. marked increase in the number of blood-plates. E. A. Locke (Boston Med. and ;...4urg. Jour., Oct. 30, 1902).
Prognosis.—The termination of this class of injuries is often of serious import especially when medico-legal questions arise. This should be determined by the several factors which arise in each case. Consideration must be given to indi viduality of the sufferer, both his age and constitutional acquirements; the ex tent of the burn, both as to surface and depth involved; the location of the in jury, and the nature of the exciting medium. The effects upon strong, ro bust subjects are not so marked as upon those of weaker constitutions, and, while the same degree or extent of burn will soon be recovered from by the former, the most dire results may follow in the latter persons. Thus it may be noticed that burns among machinists, glass blowers, plumbers, and foundrymen will not be so serious as would the same de gree or extent among clerks or those engaged in gentlemanly pursuits. Col ored persons suffer less severely than do the white. Females, on account of more delicate systems, are less able to resist shock than are the males. Middle life is not so severely affected as are children or aged people. Some persons may be able to resist the shock only to be car ried off by the complications that arise.