The blood of the dog, guinea-pig, and rabbit has red cells whose average diameter is greater than inch, and many hematologists do not consider that we are warranted, from the size of the red blood-cells alone, in expressing a positive opinion as between human blood and that of one of these animals, which may be included in the list of domestic animals. All that the expert is required to state is that these measurements (3 to 5 inch) are consistent with the human origin of the blood in question. The burden of proof always lies with the defendant to state that it is not of human origin.

The serum-test is the most delicate one thus far discovered for differentiating between the different kinds of blood, and has been shown to be applicable to both fresh and decomposed blood and to dried blood-stains.

OTHER STAINS CONTAINING BLOOD.

Diagnosis of these can be made only by finding, on microscopic examination, other formed elements mixed with the blood-cells, such as epithelial cells of various kinds, pus, dried mucus, spermatozoa, etc.

Menstrual Stains.-The possibility of determining whether or not a blood-stain was caused by menstrual blood depends largely upon the amount of hemorrhage. This, as is well known, differs with different women, and also in the same individual at different times. If the flow be scanty, as at the very beginning or end of the menstrual period, the menstrual blood will have mixed with it a large number of epithelial cells coming from the vagina. If, however, the flow is very abundant, a stain may be made by menstrual blood, particularly a small stain, which does not contain any of the vaginal cells.

The vaginal cells are large polygonal, squamous, epithelial cells, somewhat similar to those obtained from the mucous membrane of the mouth, but having on the average a somewhat larger nucleus. Sometimes we see a vaginal cell with two nuclei. These cells may be exfoliated singly or in small patches containing several layers of cells. If the vagina be inflamed, as in leukorrhea and gonorrhea, these cells will be exfoliated from the membrane in much larger number, and will be mixed with pus-corpuscles. Possibly a Possibly a cylindric or ciliated cell from the lining membrane of the uterus may be seen mixed with the blood.

If, therefore, we find mixed with the red blood-cells a number of vaginal epithelial cells, we may state that the stain in question is consistent with its having been made by menstrual blood. If, however, we do not find any vaginal cells mixed with the blood, we are not warranted in concluding that the stain was not made by menstrual blood.

The location of the stains, as upon bedding or underclothing, may possibly be of service in deciding the question as to the menstrual origin of the blood-stain in question. In uncleanly women these stains are said to be found more frequently on the back part of an undergarment than on the front.

Nasal Blood-stains. The detection of nasal blood-stains depends upon precisely the same principle as that of menstrual stains, namely,

VOL. II.-48

the finding of various morphologic elements coming from the mucous membrane of the nose mixed with the blood. These morphologic elements are coagulated mucus and cylindric or ciliated epithelial cells coming from various portions of the Schneiderian mucous membrane. If there is but little hemorrhage and the stain be made by forcibly blowing the nose, the blood will be mixed with more or less mucus and cells, and when such a stain becomes dry, it presents a very different appearance from an ordinary blood-stain; it is paler and more bulky than a blood-stain, and, after being moistened, if there is much dried mucus present, it will swell up and have a more or less elastic feel.

If the hemorrhage from the nose has been profuse, a large portion of the blood may not have mixed with it any of the mucous secretion or any of the cells, so that stains may be made from blood coming from the nose, which do not differ in any way from a pure blood-stain. In such cases the location of the stain in question may show whether or not it could have been made by blood coming from the nose. For instance, in a recent case investigated by the writer, in which the accused alleged that the blood upon his clothing was due to nose-bleed, a horizontal spatter of blood was found between the folds of a turn-down collar, in such a position that it could not have come from the nose while the collar was around the neck.

As in the case of menstrual stains, therefore, we can only state that a stain in which we have found coagulated mucus and cells mixed with the blood is consistent with its having originated from the nose. If we do not find such an admixture, we cannot say that the stain was not caused by nose-bleed unless it is so located that it would be impossible for the blood coming from the nose to have gotten into that position.

MEDICOLEGAL EXAMINATION OF SEMINAL STAINS.

THE recognition of a seminal stain upon clothing or other substance is, naturally, of great medicolegal importance in cases of alleged rape or sodomy. The variety of substances liable to be submitted to the expert for examination for seminal stains is not so great as for blood-stains. The articles usually brought for examination are pieces of bed-clothing or underclothing, and sometimes other articles of wearing apparel; in some cases scrapings from the skin or mucous membrane of the alleged victim, such as dried masses taken from the neighborhood of the genitals or tightly adherent to the hair, or scrapings of mucus from the vagina. Rarely are extraneous substances, such as pieces of wood, metallic instruments, or bits of leaves or earth submitted for examinations of this kind. Seminal stains, like blood-stains, may be either simple or complex-that is, they may consist of pure dried seminal fluid or of seminal fluid mixed with other fluids or secretions, such as blood, discharges from vagina, intestines, or other membranes.

Seminal fluid varies somewhat in its consistence according to circumstances, and in the same individual at different times. Its density may vary from 1027 to 1037; it is more or less viscid and feebly alkaline; usually it has a grayish, more or less opalescent appearance, and in rare instances it may have a reddish tint, even when not mixed with blood, and more particularly is this the case in old age. When fresh, it has a peculiar odor that is entirely lost upon drying. Formerly considerable importance was attached to the odor as a medicolegal test, but at the present time this test is never employed in dried stains, as many other substances have been found that, particularly when heated, yield an odor closely resembling that of heated seminal fluid.

The appearance of a dried seminal stain varies according to circumstances, and particularly according to the nature of the surface on which the stain is made. If found upon a non-absorbent surface, such as a piece of wood or iron, or upon heavy woolen cloth or velvet, it dries, forming a grayish scale upon the surface of the fabric, from which a portion can very easily be removed with the point of a knife-blade or a needle for microscopic examination. If cotton or linen cloth has been starched, so as to render it comparatively non-absorbent, a seminal stain will have the same scaly appearance. The color of the stain may be simply grayish or have a very faint yellowish tint, and in rare instances the stain may have a reddish tint not uncommon with the seminal fluid of old men. On unstarched cotton, linen, or any very absorbent fabric

In

a seminal stain is very difficult to see, especially if the stain be a small one. When a drop of the fluid falls upon such a fabric, it is immediately absorbed, and the fluid portion extends for quite a long distance, forming, when dry, a nearly colorless stain having a very irregular outline. some instances scarcely any change in color is produced upon the surface of the cloth, but if the cloth be held up to the light and viewed by transmitted light, the stained portion will be somewhat translucent, the meshes of the cloth being more or less filled with the dried material. The stained portion will also be found to have a stiffer feel than the unstained portion of the cloth, as is the case when such a fabric is stained with blood or any albuminous fluid. If the seminal fluid forming a stain is mixed with other secretions, the appearance of the dried stain would, of course, be modified accordingly.

The location of seminal stains may vary greatly with different circumstances. In cases of alleged rape they are found most frequently upon the underclothing of the victim or upon the clothing of the accused. In cases of rape of young girls the stains are almost invariably found upon the posterior flap of the undergarment or upon the drawers or shirt. On the undergarments of men the stains are almost invariably upon the anterior portion.

The Florence Test.-Seminal stains are diagnosticated with absolute certainty only by the recognition of the characteristic morphologic elements, the spermatozoa, by microscopic examination. The seminal fluid consists of an admixture of the secretion of several glands, the fluid portion being a solution of various organic and inorganic substances, being especially rich in phosphates, and the undissolved portion consisting of the characteristic spermatozoa and numerous cells coming from the mucous membranes lining the different portions of the seminal tract. The seminal fluid does not contain serum-albumin, but it does contain other albuminoid substances. Of the various organic substances that appear to be almost constantly present are nuclein, lecithin, cholesterin, hypoxanthin, and fatty matters rich in phosphorus ; cerebrin, guanin, and sarcin have also been found. A crystalline substance called spermin was first isolated from seminal fluid by Schreiner in 1878. It has the formula C,H,N, and gives all the general reactions of an alkaloid. It is soluble in water and absolute alcohol, but very slightly soluble in ether; its solutions have an alkaline reaction. Spermin is not peculiar to the seminal fluid of man, but has been found in that of some animals, also in sputum, blood, and some of the animal tissues. Dr. Florence,' of Lyons, claims to have discovered an alkaloidal body that he finds only in the seminal fluid of man, and that gives a characteristic crystalline precipitate with a concentrated solution of iodin in potassium iodid. Dr. Florence has not been able to obtain these crystals with the seminal fluid of any other animal, nor from any other fluid or tissue. This substance Dr. Florence calls virispermin. This test is one of extreme delicacy, a single fibril of cloth upon which is a dried seminal stain sufficing to yield numerous crystals when the test is properly performed. 1 Du Sperme et des Taches de Sperme en Médecine Légale, 1897.

The reagent, iodureted potassium iodid, is prepared in the following

manner:

Potassium iodid
Iodin. .

Distilled water

1.65 gm.

2.54 66 30.00

These proportions correspond to the formula KI,. The iodin dissolves very quickly in the solution of potassium iodid, and it is only necessary to mix the material together in a glass-stoppered bottle and allow it to stand for a short time, when the reagent will be ready to use.

The test is performed in the following manner: A very minute fragment of the stained fabric is carefully removed by means of fine-pointed forceps and sharp-pointed scissors, transferred to a glass slide, treated

with a small drop of distilled water, allowed to soak for a minute or two, a minute drop of the iodin reagent added to it in such a way that the two drops of fluid come in contact by their edge, and immediately covered with a covering-glass. If the suspected stain contained any dried seminal fluid, the examination with the microscope will show a very large number of brown crystals that resemble in appearance the hemin crystals obtained by performing Teichmann's test with blood. The accompanying illustrations (Figs. 84, 85, and 86) show these crystals, which were obtained from a single thread of an inch long cut from the stained portion of a pair of child's drawers in a case of attempted rape, the stain being three years and four months old at the time the test was made.

If the stain examined be one upon a non-absorbent surface, like a piece of wood, it is sufficient to remove a very minute fragment of the