Page:The American Cyclopædia (1879) Volume II.djvu/759

BLOOD STAINS 739 with rose or purple. All parts of the plant are pervaded by an orange-colored sap, of deepest color in the root. They all possess the Bame medicinal qualities, but the root only is Bloodroot (Sangalnaria Canadensls). made use of. This is dried and pulverized, and is administered while fresh, either in the powder, or in pills prepared from it for the purpose of avoiding the irritating effect of the powder upon the throat, and also in infusion or decoction and tincture. Its properties are those of an acrid narcotic and emetic, in over- dose producing violent thirst, faintness, and dimness of vision. In some cases ita effects have been fatal. Upon fungous surfaces it acts as an escharotic. It has been found useful in numerous diseases, among which are typhoid pneumonia, catarrh, scarlatina, rheumatism, jaundice, dyspepsia, &c. Many physicians have long relied upon it wholly for the cure of croup. Its active properties appear to reside in a peculiar alkaline principle called san- guinarine, which is separated in the form of a white pearly substance. This has an acrid taste, and forms with the acids salts, all of which, when dissolved in water, produce beau- tiful red colors. BLOOD suns. Various medico-legal ques- tions are often to be solved concerning the na- ture of stains resembling those made by blood. The principal of these are : 1. Is it possible, and by what means, to decide that a stain is pro- duced by blood or not ? 2. Is it possible, and by what means, to ascertain that the blood of a stain comes from a man or from an animal ? 8. Is it possible to find out whether the blood of a stain comes from one man or another ? I. It is usually easy to ascertain whether a stain is due to blood or not, either by the chemical test of reagents or the physical test of the microscope. The latter is the more decisive, but a complete medico-legal examination must comprise both of them. If there is a stain of suspected blood on a piece of cloth, or any other stuff, the stained part must be cut off and dipped into a small quantity of distilled water. In the course of a few hours the coloring matter, if it is that of blood, will detach iti-elf and reach the bottom of the vessel, the supernatant fluid remaining tolerably clear or slightly rose- colored. The fibrine will remain attached to the stuff as a grayish or rosy-white substance. If the liquid be boiled, the color will be destroy- ed and the albumen coagulated ; in its inferior parts, where the coloring matter has accumu- lated, the liquid will become grayish or green- ish, while the upper portion will acquire a slightly yellow tint. The red soluble dyes, or stains from the juices of fruits, are very rarely coagulated, and they do not lose their color when, after having been dissolved in water, the solution is boiled. Besides, they are rendered crimson or green, passing sometimes to violet, when treated with ammonia, while this reagent, unless it be used in great quantities and con- centrated, does not change the color of blood or of a watery solution of a blood stain. When ammonia is powerful enough to alter the color of blood, it gives it a brownish tint, instead of the crimson, green, or violet colors that it gives to dyes. If the solution of a blood stain has co- agulated by boiling, we find that potash dis- solves the coagulum, rendering it limpid and green by reflection, and pink by refraction. If chlorhydric acid is then added, the transpa- rency disappears, but it returns if another quantity of potash is added. These reactions belong only to blood. The nature of the small- est stain, able only to furnish one drop of a so- lution, may be found out by the above-mention- ed chemical means. In such circumstances, according to Boutigny, the drop should be thrown into a silver spoon at a very high tem- perature. The liquid in this, as in any other case, i. e., with any kind of liquid whatever, being suddenly exposed to an extreme heat, instead of evaporating takes the shape of a sphere, and then experiments may easily be tried, and the action of ammonia, of potash, of chlorhydric acid, &c., may rapidly be ascer- tained. The microscope usually shows more quickly and positively than chemical reagents whether a stain is due to blood. With the help of this instrument the red and the colorless corpuscles may be seen easily. (See BLOOD.) There is nothing to be found with the micro- scope in the stains of the various dyes which can in any way be mistaken for the blood cor- puscles. The presence of these well charac- terized particles in a stain is therefore an in- contestable proof that it contains blood. But the blood corpuscles may have become so much altered that it is very difficult to ascertain their presence, at least without the help of chemical reagents. The microscope, unaided by chem- istry, therefore, may fail to detect blood in old stains. However, it is usually easy to find the red corpuscles, and they have been detect- ed in stains of many years' duration. Dr. Tay-