DETERMINATION OF THE NATURE AND COLOR OF THE HAIR AND BEARD.
A criminal, in order to conceal his identity, may change the color of the hair and beard by artificial means; either to a darker shade, in case they were naturally of a light color, or, to a lighter hue, if they were originally dark, and the chemical expert may be called upon to detect this artificial coloration, and restore the original color of the hair.
It may also happen, that portions of hair still adhere to the clots of blood sometimes found on an instrument which has been employed in the commission of a crime, and consequently the question may arise as to the nature of the hair, whether it be human or animal.
DETERMINATION OF THE COLOR OF THE HAIR AND BEARD.
The mode of examination necessary when the hair has been blackened is different from that used when it has been decolorized.
The hair has been blackened.
As various methods of dyeing hair black are in use, the means of restoring the original color differ. The following are the methods most usually employed in dyeing:
1º. The hair is well rubbed with a pomade, in which finely pulverized charcoal is incorporated. This preparation, which is sold under the name of "mélaïnocome," possesses the disadvantage of soiling the fingers and clothing, even for several days after its application.
2º. The hair is moistened with a dilute solution of ammonia, and a perfectly neutral solution of a bismuth salt (chloride or nitrate) is then applied. It is subsequently washed, and allowed to remain in contact with a solution of sulphuretted hydrogen.
3º. The same operation is performed, a lead compound being substituted for the bismuth salt.
4º. A mixture of litharge, chalk, and slacked lime is applied, and the head covered with a warm cloth. The hair is afterwards washed, first with dilute vinegar, then with the yolk of an egg.
5º. The hair is first cleansed with the yolk of an egg, and then moistened with a solution of plumbate of lime; or,
6º. It is moistened with a solution of nitrate of silver, to which a quantity of ammonia sufficient to dissolve the precipitate first formed has been added.
The first method merely causes a mechanical admixture of a coloring matter with the hair. In the four succeeding processes, a black metallic sulphide is produced; either by the subsequent application of a solution of sulphuretted hydrogen, or by the action of the sulphur normally present in the hair.
In the last method, the formation of sulphide of silver doubtless occurs; but the principal change that takes place is probably due to the action of light, which, as is well known, decomposes the salts of silver.
In order to restore the original color to hair which has been treated with "mélaïnocome," it is only necessary to dissolve in ether the fatty matters present, and then remove the charcoal by washing with water.
In case the hair has been dyed by means of a bismuth or lead salt (as in methods 2, 3, 4 and 5), it is immersed for several hours in dilute hydrochloric acid: the metal present dissolves, as chloride, and the original color of the hair is rendered apparent. It then remains to detect the metal dissolved in the acid solution, in order to establish, beyond doubt, the fact that a dye has been employed. This is accomplished by means of the methods used for the detection of metals in cases of supposed poisoning.
If, finally, an ammoniacal solution of nitrate of silver has been employed to cause the coloration, the hair is immersed, for some time, in a dilute solution of cyanide of potassium, and the fluid subsequently examined for silver. In case a portion of the salt has been converted into the sulphide, it will be difficult to restore the original color, as the removal of this compound is not easily effected.
The hair has been decolorized.
Black hair can be bleached by means of chlorine-water, the various shades of the blonde being produced by the more or less prolonged action of the reagent. In this case, the odor of chlorine is completely removed only with great difficulty, and the hair is rarely uniformly decolorized. The expert may therefore be able to observe indication that will greatly assist him in arriving at a definite conclusion. The hair should be carefully examined up to the roots: if several days have elapsed since the decolorization has been performed, the lower portion of the hair will have grown and will exhibit its natural color. No method has yet been proposed that restores the original color to bleached hair. It is very possible, however, that this end would be attained by allowing nascent hydrogen to act upon the decolorized hair. For this purpose, it would be necessary to immerse it in water containing some sodium amalgam, and slightly acidulated with acetic acid.
DETERMINATION OF THE NATURE OF THE HAIR.
In examinations of this character use is made of the microscope. The hair to be examined is suspended in syrup, oil, or glycerine and placed between two thin glass plates. Human hair is sometimes cylindrical; sometimes flattened. It consists either of a central canal, or of a longitudinal series of oblong cavities which contain oily coloring matter, and possesses the same diameter throughout its entire length. The brown hair of the beard and whiskers, medium-sized chestnut hair, the hair of a young blonde girl, and the downy hair of a young man possess respectively a diameter of 0.03 to 0.15; 0.08 to 0.09; 0.06; and 0.015 to 0.022 millimetres. These exhibit on the surface slightly projecting scales, which are irregularly sinuous at the border, separated from each other by a space of about 0.01 m.m., and are transparent, whatever may be their color.
The hair of ruminants is short and stiff, and is characterized by containing cavities filled with air. Wool, however, forms an exception, as it consists of entire hairs, homogeneous in appearance and possessing imbricated scales, which bestow upon it the property of being felted.
The hair of the horse, ox and cow never exceeds 12 m.m. in length, and is tapering, its diameter gradually diminishing from the base. It is perfectly opaque, and does not appear to possess a central canal; has a reddish color, and frequently exhibits lateral swellings, from which small filaments occasionally become detached, in the same manner as a twig separates itself from the parent branch.
EXAMINATION OF FIRE-ARMS.
(Proposed by M. Boutigny.)
The examination of fire-arms is sometimes useful in determining the date at which a weapon has been discharged or reloaded. The methods used in examinations of this nature vary, as the weapon under inspection is one provided with a flint or an ordinary percussion lock. The value of the tests employed is also affected by the kind of powder used; i. e., whether common gunpowder, gun-cotton or white gunpowder (prepared by mixing yellow prussiate of potassa, chlorate of potassa and sugar) has been taken.
THE GUN IS PROVIDED WITH A FLINT-LOCK, AND WAS CHARGED WITH ORDINARY POWDER.
In case the weapon has been wiped or exposed to moisture subsequent to its seizure, it is impossible to form any conclusion as to the date of its discharge, etc. It is therefore advisable, upon receiving the weapon, to carefully wrap the lock in a woollen cloth, and to close the barrel. The exterior of the gun is at first submitted to a careful examination, and notice taken of the approximate thickness of any existing rust spots. The fire-pan and adjacent portion of the barrel are also examined by aid of a magnifying glass, especial attention being given to the detection of traces of a moist and pulverulent incrustation of a greyish or blackish color, formed by the combustion of the gunpowder, and of crystals of sulphate of iron. If the weapon is loaded, the wad is withdrawn and the color of its cylindrical portion and of the powder, as well as the size of the ball or shot, noted.
This preliminary examination ended, the barrel and fire-pan are separately washed with distilled water, and the washings passed through filter paper which has previously been well washed, first with pure hydrochloric acid, then with distilled water. The filtrate is next divided into three portions, and these separately examined for: (1) sulphuric acid, by addition of chloride of barium; (2) for iron, by oxidizing the salts contained in the fluid with a few drops of nitric acid and adding a solution of ferrocyanide of potassium, the presence of iron being indicated by the formation of a blue coloration, or a blue precipitate; and (3) for sulphides, by means of a solution of subacetate of lead.
If a bluish-black incrustation is discovered on the fire-pan or on the neighboring portions of the barrel, and both rust and crystals of sulphate of iron are absent, and the washings, which were originally of a light-yellow color, assume a chocolate-brown coloration upon the addition of solution of subacetate of lead, the gun has been discharged within two hours at the longest.
If the incrustation possesses a lighter color and traces of iron have been detected in the washings, but neither rust nor crystals have been discovered on the barrel or fire-pan, the weapon has been discharged more than two, but less than twenty-four hours.
In case minute crystals of sulphate of iron and spots of rust are found, and the washings contain iron in a considerable quantity, the weapon has been discharged at least twenty-four hours, at the longest ten days.
If the quantity of rust found is considerable, but iron is no longer to be detected, the discharge of the gun occurred ten days, at the longest fifty days, previously.
If the weapon has been reloaded immediately after its discharge without having been previously washed, the portions of the wadding which have come in contact with the barrel will possess a greyish-black color during the first four days, the color gradually becoming lighter, until, at the fifteenth day, it turns grey and remains so permanently. In this case, the washings will contain sulphuric acid. The objection has been advanced to the last test that sulphuric acid might be discovered, even if the gun had not been discharged, if the paper of which the wadding was made contained plaster. M. Boutigny states, however, that this objection is untenable, if the wadding has not been moistened by the water introduced into the barrel.
In case the gun has been washed and dried before being reloaded, the cylindrical portion of the wadding possesses an ochre-yellow color up to the first or second day, assumes a decided red hue on the days following, and acquires a clear rusty color on the sixth day. During the fifth day the powder also possesses a reddish appearance, owing to an admixture of rust. Sulphuric acid is not present in the washings.
If the weapon has been reloaded immediately after being washed, the wadding possesses a greenish-yellow appearance for the first few hours, and subsequently acquires a reddish color, as in the preceding case.
If, finally, the barrel has been washed with turbid lime-water, rust is still to be found and the wadding possesses the color mentioned above. The following colorations are also to be observed in case the gun has not been washed, or has been dried near a fire:
| BARREL DRIED NEAR A FIRE. | UNWASHED BARREL. | |
|---|---|---|
| After 1 day | slight reddish yellow color | greenish yellow color. |
| — 2 or 3 days | a little darker " | reddish-brown " |
| — 4 days | a redder " | reddish-brown " |
| — 5 or more days | a rusty-red " | rusty-red " |
THE GUN IS NOT PROVIDED WITH A FLINT LOCK.
At present weapons having flint-locks have almost entirely gone out of use and have been superseded by the ordinary percussion gun; these latter, in turn, are being gradually replaced by breech-loaders, charged with or without a metallic cartridge. The indications obtained in the preceding examinations by means of the fire-pan, will therefore disappear; the results given by the inspection of the barrel may possibly hold good. In regard to breech-loaders, all the useful indications furnished by the coloration of the wadding and powder fail to occur; the latter being enclosed either in a paper cylinder or in a copper socket.
The fact that gun cotton and white gunpowder are occasionally made use of, adds to the difficulty of obtaining reliable results by the mere inspection of a weapon. White gunpowder does not oxidize the gun, fails to give rise to any salt of iron, and possesses a white color; gun-cotton produces distinctive indications varying with its purity. Owing to these facts, it is evident that the method proposed by M. Boutigny is of no real value, save in the rare instances where a gun provided with a fire-pan, and charged with ordinary powder, is under examination, and the question of the lapse of time since the discharge of a weapon must remain undetermined so far as scientific tests are concerned.