IV. MISCELLANEOUS EXAMINATIONS. (continued 2)

If upon adding some of the substance under examination to the above mixture a clear blue coloration ensues, and the insoluble matter thrown down possesses a deep blue color, the presence of coloring matter of the blood is indicated. The mixture also imparts a blue color to moistened spots from which the blood stains have been as completely extracted as possible. Unfortunately sulphate of iron gives the same reaction.[X]

b. Upon heating the fluid obtained by treating the stains with cold water in a test-tube, its brown or reddish color disappears, and greyish-white flakes of coagulated albumen are thrown down. The precipitate acquires a brick-red color, when treated with an acid solution of nitrate of mercury containing nitrous acid. The albumen is also coagulated by the addition of nitric acid: it assumes a more or less yellow color, if heated with a slight excess of the acid. Chlorine-water, especially upon heating, likewise precipitates albumen in the form of white flakes.

c. If the fluid is acidulated with a few drops of acetic acid, and a drop of ferrocyanide of potassium added, a white precipitate, or, at least, turbidity is produced.

d. The flakes of albumen, separated by heating, dissolve in caustic alkalies to a solution, from which they are re-precipitated by nitric acid, or chlorine water.

e. Upon treating blood stains with chlorine-water, a solution which contains chloride of iron, and acquires a red coloration by the addition of sulphocyanide of potassium, is formed.

f. Should the stains have failed to be affected by cold water (which, as has already been remarked, is the case when they have been previously washed with hot water), they are treated with weak soda lye. Nitric acid, hydrochloric acid, and chlorine water will produce in the solution so obtained a white precipitate, which exhibits the general properties of albumen previously described. In case the stains are deposited upon linen, it is necessary to replace the soda by ammonia, in order to avoid dissolving the fabric.

g. Solutions of the alkalies, which dissolve the albumen, leave the coloring matters intact, and consequently do not decolorize the fabric. If the latter is afterwards subjected to the action of hydrochloric acid, the coloring matter is dissolved, forming a solution that leaves upon evaporation to dryness a residue containing iron, which gives a blue coloration with ferrocyanide of potassium, and a red coloration with sulphocyanide of potassium.

h. The coloring matter of blood dissolves in boiling alcohol, to which sulphuric acid has been added, to a brown dichroic fluid (appearing green by transmitted light, and red by reflected light). A mixture of rust and blood exhibits the same phenomenon.

i. If substances containing blood are heated in a dry tube, an odor resembling that of burnt horn is emitted. In case the stained fabric is a substance that would produce this odor, (such as wool, silk, or hair), the test naturally loses all value.

j. If the fluid obtained by treating the stains either with water or alkali is evaporated with a little carbonate of potassa, and the residue heated, at first at 100°, then to redness, in a glass tube to which a fresh quantity of carbonate of potassa has been added, cyanide of potassium is formed. When cold, the tube is cut above the part containing the fused mixture, the mass heated with iron-filings and water, the fluid filtered, and the filtrate then acidulated with hydrochloric acid: ferrocyanide of potassium will be present in the fluid, and upon adding a drop of solution of perchloride of iron a green, or blue, color will be produced, and a precipitate of Prussian blue gradually thrown down.

If the stained cloth is non-nitrogenous (per ex.: hemp, linen, or cotton), instead of treating it with water, it may be heated until pulverulent, mixed with carbonate of potassa, the mixture calcined, and the operation then completed as just described. This test having given affirmative results, the operations should be repeated with an unstained portion of the cloth, to remove all doubt that the indications obtained do not really originate from the fabric.

In the present state of science, it is impossible to discriminate chemically between human and animal blood. M. Barruel, it is true, is able, not only to accomplish this, but also to distinguish the blood of the various species of animals by its odor! But this test has a somewhat hypothetical value for scientific purposes. In regard to the crystals of haemin, they do not present sufficient difference to allow the blood of different animals to be distinguished. We have not yet treated of the globules. It often occurs that these minute organs are so altered as to be no longer recognized in the microscopic examination; when, however, the stains are tolerably recent, they may be detected by examining the moistened stained cloth, directly under the microscope: a discrimination between animal and human blood is then possible: corpuscules of human blood possess the greater size: those of the sheep, for instance, have only one-half the diameter of the former. It is, however, but seldom that this distinction can be made use of.[Y]

EXAMINATION OF SPERMATIC STAINS.

In cases where attempt at violence, rape or pederasty is suspected, the expert may be required to determine the nature of stains found on clothing, sheets, etc. The fact that the stains were produced by semen, may often be regarded, per se, as criminating evidence. This class of investigation possesses, therefore, considerable importance.

External appearance of the stains.—Dry spermatic stains are thin, and exhibit a greyish or, occasionally, a citron-yellow color, if present on white cloth. In case the fabric is colored, they appear whitish and, if on linen, present a glossy aspect. They are translucid, when observed by transmitted light. If the fabric, upon which the stains are deposited, is of a heavy texture, they are visible only on one side: under all circumstances, their circumference is irregular and undulated. These indications, however, are not conclusive, but vary according to whether the stains were produced by the thick semen of a vigorous man, or the aqueous seminal fluid of an aged and diseased person, or by semen more or less mixed with the prostatic fluid. Upon moistening spermatic stains, the distinctive stale odor of fresh semen is sometimes emitted, but this characteristic is usually obscured by the presence of foreign substances.

Semen stains are soluble in water, forming a gummy fluid, in which chlorine, alcohol, bichloride of mercury, acetate and subacetate of lead produce a white precipitate, but which fails to be coagulated by heating. Plumbate of potassa does not impart a fawn-color to these stains, at a temperature above 20°, as is the case with those produced by albuminous substances.

Persulphate of iron imparts to spermatic stains a pale yellow color,

Sulphate of copper, a bluish grey color,

Cupro-potassic tartrate, a bluish grey color,

Nitrate of silver, a pale grey color,

Nitric acid, a pale yellow color.

The above reactions, separate or united, are insufficient; they are not very delicate, and are likewise produced by stains originating from the other varieties of mucus: the indications furnished by a microscopic examination of the stains are alone conclusive.

Microscopic examination.—Semen contains as its principal and fecundating constituent, peculiar vibratory filaments, (spermatozoa), held suspended in a viscous fluid. These filaments, when preserved in a warm and moist place, retain their activity for a considerable time: it is even possible that they may exhibit vitality in the organs, into which they have been voluntarily or forcibly ejaculated, for ten, or even twenty-four hours. When exposed to cold air, the spermatozoa quickly expire; still, they preserve their form for some time, and, as this is very characteristic, it is then easy to identify them; moreover, since they originate exclusively in the testicles, their detection may be considered as certain evidence of the presence of semen. In stains produced by aged persons, and by persons enfeebled by excesses, the spermatozoa fail to be presented; in case they are discovered, this fact evidently does not affect the certainty of the spermatic origin of the stains. The contrary conclusion is never absolutely certain: still, if the use of the microscope fails to establish the presence of spermatozoa, it is almost certain that the stains were not produced by semen.

Of the various methods for obtaining from the stains a preparation adapted to the microscopic examination, the one proposed by M. Charles Robin is the most simple and reliable.

A strip, 1 c. c. in size (comprising the entire stain, if this be small, containing its inner portion, if it be large), is cut from the fabric under examination, care being taken that the two extremities of the sample extend beyond the stained portion.

One end of the cloth is then immersed in a capsule, or watch-glass, containing pure water: the stains become moistened by capillary attraction, and, in a space of time varying from twenty minutes to two hours, acquire the appearance of fresh semen. As soon as the stained portion becomes swollen and softened, the surface of the cloth is gently scraped with a spatula, and the substance removed placed on the slide of the microscope. The particles are next slightly detached, a drop of water added, if necessary, and the whole covered with a small plate of very thin glass. The preparation is then examined by a microscope, having a magnifying power of from 500 to 600 diameters. In this way, the presence of either entire or broken spermatozoa is readily detected. Their existence is rendered still more apparent, if the mucus present is dissolved by adding a drop of acetic acid to the preparation.

Entire spermatozoa consist of long slender filaments, having a length of 0.04041 to 0.04512 millimetre; the anterior extremity presents an oval enlargement, either round or pyriform, exhibiting a double outline, when magnified to 500 diameters. This enlarged end is termed the "head;" the entire remaining portion being regarded as the "tail." In case the spermatozoa are broken, they are severed either near the head or in the middle of the tail, and a mass of detached fragments will be observed in the microscopic examination. The spermatozoa are not the only corpuscules revealed by the microscope; other substances, entirely different in character, are often observed. Although the detection of these bodies is, in itself, of no value, it will be well to enumerate and characterize them; they are:

a. Oily globules.

b. Leucocytes, or spherical and finely granulous globules of mucus.

c. Corpuscules, originating from the seminal vesicles, termed sympexions. These are rounded or ovoid, possess an irregular outline, and are usually mixed with the spermatozoa and globules of mucus.

d. Crystals of phosphate of magnesia, varying greatly in size; the largest are from 0.mm. 001 to 0.mm. 002 in length. The crystals formed upon cooling the semen, present the form of an oblique prism, with a rhomboidal base. Occasionally they are elongated and flattened; they then assume the form of a rhomboid.

e. Epithelial cells; originating from the mucous follicles of the urethra.

f. Irregular grains of dust; soluble in acetic and hydrochloric acids, with gaseous evolution.

g. Brownish-red grains of rust; only slightly soluble in acetic acid, but easily soluble in hydrochloric acid.

h. Filaments of the strained fabric; detected by their texture, and general appearance.

i. Grains of starch, in case the cloth has been stiffened. These are almost invariably swollen, and are frequently broken and deformed.

If the examination is to be secretly executed, and the cloth cannot well be cut, it is rolled in a cone, in such a way that the external side contains the stained portion. The lower extremity of the cone (which should be free from stains) is dipped in a watch-glass containing water, so as to avoid directly wetting the stains. The cone soon becomes moistened by absorption, and the operation is then completed in the same manner as when the fabric has been cut; which is always preferable, when possible.

The examination of spermatic stains consists, then, in moistening the stains with water, separating them as completely as possible from the stained cloth, and determining the presence of the spermatozoa by means of the microscope.

All other tests are valueless; even their execution for confirmatory purposes is not advisable; inasmuch as they fail to possess a distinctive character, and the reagents employed in their production may destroy the fabric, and thus prevent the formation of the only conclusive reaction—the detection of the spermatozoa.

In case the stains are deposited upon a woman's chemise, they are usually present on both the front and back portions, and are sometimes to be found on the sleeves. When a man's shirt is under examination, especial attention should be given to the anterior portions. The pantaloons are also often stained; usually in the interior, but sometimes also on the exterior, just above the thighs. In reporting the decision to the court, as to the nature of the stains, their precise position should invariably be stated, as, by this means, the circumstances attending the commission of the crime may be, at least partially, elucidated.

THE END.