established. It was on other evidence that the prisoner was acquitted on January 25, 1904.

semble blood corpuscles. The measure 15 c. c. of perfectly clear serum were ment of red blood corpuscles in very obtained on the following day. This old stains is not satisfactory. The enserum was tested on human blood, but tire disintegration of the clot and the no specific reaction was obtained. The separation of individual corpuscles in mixture of the solution of blood and sufficient numbers for accurate results antiserum remained perfectly clear for are difficult and sometimes impossible. ten hours, when a slight cloudiness apThe corpuscles, when separated out, are peared. Quite discouraged by these not fixed and stationary, and the slight- unlooked for results, I wrote to Dr. est movement prevents accurate Patek and Dr. Bennet, who had emmeasurement. Besides, for medico- ployed this method in a medico-legal legal purposes, the adverse opinion as case with satisfactory results. These to the value of the method, expressed gentlemen could not explain my failure, by such eminent authorities as Vibert, and sent me about 2 c. c. of antiWormley, Mason, Ewell, and Chapman, serum which they had obtained completely undermines the medico- a month previously. This antilegal status of this method. The only serum I tested on human blood and real value of the microscopical examina- obtained a marked specific reaction in tion of the blood is in distinguishing mammalian from avian blood, and in our case the microscope enabled us to exclude with absolute certainty some blood stains which were made by bird's blood, thus indicating that the murder was not committed in the chicken house, as was at first suspected.

The

two hours. An inquiry directed to Professor Flexner elicited the reply that he could offer no explanation for my failure. Fearing that perhaps the amount of blood injected was not sufficient to produce a strong antiserum, I injected into one of the remaining rabbits two more doses, 10 c. c. each, of placental 3. The biological or serum test. To blood, at intervals of five days. Ten apply this test three rabbits were days after the last injection I opened treated with human blood obtained the right femoral artery between two from the placenta. Several physicians loosely held ligatures, and by means of were supplied with sterile, wide-mouth a small glass cannula obtained about bottles, and instructed to slip in the 5 c. c. of blood. The vessel was then placental end of the cord as soon as ligated and the wound closed. No ill severed, and allow the blood to run into results followed this operation. the bottle. Usually from half an serum obtained from this rabbit's blood ounce to two ounces of blood were ob- was tested as before, and found to postained each time. The bottles were sess marked precipitating properties, placed in the refrigerator, and the giving the specific reaction with human serum drawn off on the following day. blood, highly diluted, within thirty At first, 5 c. c. of the serum were in- minutes. This antiserum was used for jected into each animal. Three days the medico-legal test according to the later 8 c. c. were injected, followed by following method: One-drachm long 10 c. c. five days later, and this dose homeopathic vials were obtained. A was repeated until six injections had portion of each blood stain was scraped been made altogether. On two oc- off into an Erlenmeyer flask, and norcasions the blood which had been kept mal salt solution added. The flask was in the refrigerator for a week was used agitated at frequent intervals until the without any ill results. Except for a solution became perceptibly colored. slight elevation of the temperature and It was then filtered twice and enough a general indisposition following the salt solution added to the filtrate to first two injections, the animals showed make the red tint barely perceptible. no bad effect from the treatment. At The vials were then filled, leaving just the expiration of one week after the room enough for the antiserum, of last injection, one of the rabbits was which two drops were added to each vial. bled to death by severing the jugulars, The vials were stoppered and placed in and about 25 c. c. of blood obtained in the incubator at 37° C. At the end of a small Erlenmeyer flask. The blood every five minutes for thirty minutes, clotted rapidly and firmly, and about and every half hour for two hours, the

cation of human blood, and if positive rendered the presence of human blood highly probable. I was not willing to state that the presence of human blood was established "beyond a reasonable doubt," for the reason that this was my first experience with the test, and I did not feel that I was ready to assume the moral responsibility. I felt confi dent, however, that, all things being equal, this test furnished more reliable evidence of the presence of human blood than could have been attained from the most exact measurements of corpuscles. As to the latter the warmest advocates of the method claimed only a "consistency with a theory." From a perusal of the rather voluminous literature and my own experiments, I am now convinced of the specific nature of the serum test. Whatever discrepancies may be discovered in the observation of various authors, they can well be ascribed to faulty technique. In this test, as in the Widal test, both dilution and time should be taken into

13. Horse's blood serum, several consideration. Given a high dilution weeks old.

14. Rabbit's blood on filter paper. 15. Stain on quilt with which the murdered woman was covered, stain six months old.

(a barely perceptible tint to the solution) and a short time (half an hour to two hours), the appearance of distinct clouding is conclusive evidence that the blood is homologous with that Nos. 1, 2, 5, 9, 10, and 15, showed a used in the immunization. The lower distinct clouding within thirty minutes, the dilution and the longer the time rethe precipitate gradually subsiding to quired to produce the specific reaction, the bottom. All other solutions re- the less likelihood is there that the mained perfectly clear for twelve hours, blood is that sought. Under these cirwhen a slight clouding appeared. The cumstances the serum test should be actests were repeated with another portion of rabbit's serum, obtained several days later, from the left femoral artery of the same rabbit, with identical results. The objects Nos. 1, 2, and 5, as was subsequently learned, were obtained from the corncrib; Nos. 3, 7, 8, from the chicken house, and the manure from a tomato patch in the garden. (The microscopical examination of stain 3 showed nucleated red corpuscles.)

These findings formed the basis for the theory that the woman was killed in the corncrib, and then removed to the barn, a theory which seemed to be supported by other evidence. It is thus seen that by means of the serum test all blood stains which we had reason to believe were not made by human blood were excluded with a degree of certain ty not attainable by any other known method. On the witness stand I made the statement that this new test was superior to any other for the identifi

corded the same position in forensic medicine as that given to other expert evidence susceptible of scientific demonstration.

The court was willing to accept the new serum test as superior to the older method of measuring the corpuscles, and the jury was charged accordingly. The defense was also willing to accept the new test as reliable, being guided, I believe, by the opinion of the authorities whom they consulted.

Conclusions.

1. Human blood can be distinguished from that of other animals, except, perhaps, monkeys, by means of antiserum. 2. Antiserum may be obtained by immunizing rabbits against human blood. 3. For immunization it is most convenient to employ the blood obtained from a human placenta, which can be secured aseptically without much difficulty.

4. From six to eight injections, 8 to 10 c. c. each, should be made at

6. To obtain the serum from rabbits for testing purposes it is not necessary to sacrifice the animal, as sufficient blood is human. serum can be secured from any of the large veins or arteries, the femoral being the most accessible.

298. Agents causing burns.

CHAPTER IL

BURNS AND SCALDS.

299. Classification according to severity.

300. Danger from burns; extent.

300a. Complications.

300b. Burn scars.

301. Causes of death.

302. Post-mortem examination; local lesions.

302a. Internal lesions.

302b. Other causes of death.

303. Duration of life after fatal burns.

304. Post-mortem burns; first degree; reddening.

304a. Second degree; vesication.

304b. Third degree; eschar.

304c. Fourth degree and more severe; carbonization.

305. Time for combustion of body.

306. Identity of charred body.

307. Spontaneous combustion.

308. Spontaneous ignitability. 309. Increased combustibility.

298. Agents causing burns.—A burn is the result of the action of heat upon the body. The heat may be brought in contact with the body either by a hot, solid substance, such as a red-hot iron or a burning brand, by hot liquids or molten metals, or by highly heated gases, such as steam. Certain substances by their chemical action are also distinctly caustic, and have results which are considered also as burns; and here, too, are classed the results of friction on the body in what are called "brush burns."

Heated solids produce distinctly circumscribed burns which show the portion of the body that was in contact with the heated substance. The burn may be severe or slight, depending upon the temperature of the body and the length of time that it is in contact with the flesh. Solids that are burning give a central area similar to that of the hot solid, and, in addition, a surrounding zone of less burning, which is not so sharply defined, and in which the hairs on the skin, if exposed, are singed. Portions of the body which are protected by clothing held firmly to the skin, as in the region of the belt or the garters, are

usually protected from the action of flames. Liquids give a more diffused area of burning, and a comparatively mild degree of burn. There is no singeing of the hair in the vicinity. Such hot liquid burns are popularly called scalds. Burns from gas in the state of combustion or flame produce the most severe burns, with combustion of the tissues of the body. Burns by solid caustics are similar to those by hot solids, though no high temperature is needed for the action of the caustic. Liquid caustics produce burns similar to those of hot liquids, but differ in that their line of action may be much. more limited; for a single drop of sulphuric acid, for instance, running over the skin will cause a distinct burn, while a single drop of boiling water running over the skin would soon become cooled off and lose its effect. Brush burns are such as follow after friction from a rope, for instance, running through the hands, and such burns are sharply limited to the area over which the rope ran.

299. Classification according to severity.-According to their gravity burns have been classified by Dupuytrens as follows:

1st degree: Reddening of the skin, without the formation of blis

ters.

2d degree: Formation of blisters, which contain clear or sometimes opaque serum of a yellowish color, at times tinged with blood.

3rd degree: Destruction of the external surface of the skin. The portion which has lost its vitality is seen in the form of an eschar which is soft and yellow if made by a hot liquid, but hard and brown or black if made by a heated solid, or burnt with flame. Surrounding this there is usually an area burnt to the first or second degree.

4th degree: Disorganization of the whole thickness of the skin. These burns differ from the third-degree burns only by the greater thickness of the sloughs.

5th degree: Not only the skin, but also the subcutaneous cellular tissue and a portion of the muscles, are destroyed. The injury is graver than the preceding form, though the external appearances are not strikingly different.

6th degree: Complete carbonization of the burned part.

300. Danger from burns; extent. The danger from burns is proportional rather to the extent of surface involved than to the depth of the burn. Burns of the first degree, covering two thirds of the body surface, are rarely recovered from. Burns of the second degree, or any of the severer degrees, involving one third of the body, are almost always fatal. Though Maschka reports the case of a man who, while drunk, had whisky poured over him and lighted. More