Detection.—There is but one really satisfactory plan for detecting phosphorus in organic mixtures, that invented by Mitscherlich. The suspected material is introduced into a retort, and acidulated with sulphuric acid. The stem of the retort is conducted into a glass vessel kept cool by a stream of water on the outside. The retort is heated, and distillation allowed to go on in the dark. If phosphorus be present it passes over as vapor, and is condensed in the cool vessel beyond. At each condensation a flash of light is perceived, which is the test relied on.
Chronic Poisoning by phosphorus used to be exceedingly common among match manufacturers, but is now, comparatively speaking, rare, allotropic or amorphous phosphorus being much more generally employed than it used to be, and the ventilation of the workshops being better. Its subjects used to be attacked with caries of the gums, gradually extending and implicating the jaw, and giving rise to great deformity.
[CHAPTER XV.]
ARSENIC.
Arsenic is by far the most important of metallic poisons, whether we consider the deadliness of its effects or the fatal frequency with which they are made manifest. Arsenic exists as an impurity in several metallic ores, notably in iron pyrites, which being commonly employed as a material for the manufacture of sulphuric acid, renders arsenic one of the most frequent impurities of commercial oil of vitriol. This should never be forgotten in testing any substance for the poison. To the common medicinal preparation of arsenic, consisting of arsenious acid, or arsenites, and the so-called chloride of arsenic, must be added the arseniates of potash and soda; the sulphides of arsenic—as, the red sulphide, or realgar, and the yellow sulphide, or orpiment; the arsenite of copper, or Scheele’s green, and others. They all produce similar symptoms, and poisoning by either of them requires nearly the same treatment.
According to Von Tschudi, some of the peasants in parts of Styria and Hungary eat arsenic, taking from two to five grains daily; the men doing so in order that they may gain strength, and be able to endure fatigue, the women that they may improve their complexions. These statements are so contrary to all that we know of the power of this poison, that they have been regarded as unworthy of credit. Evidence has, however, been brought forward by Dr. Craig Maclagan, of Edinburgh, which shows clearly that arsenic-eating is something more than a mere fiction. This gentleman gave, and saw a Styrian eat, a piece of arsenious acid, weighing over four grains, and afterwards determined the presence of arsenic in urine passed in his presence by the said peasant. Advantage was taken of these reports in the trial of Miss Madeline Smith (Edinburgh, July, 1857), when the court was asked to believe that arsenic found in the possession of the prisoner was used by her as a cosmetic.
Arsenite of Copper, in one form or another, either as Scheele’s green, emerald green, Brunswick green, &c., is unfortunately largely employed in the manufacture of green paper-hangings, artificial flowers, toys, and even some kinds of confectionery. Too many cases of ill-health caused by this practice have been recorded to permit any doubt as to its deleterious effects. These may be manifested by people living in rooms furnished with such paper-hangings. The chief symptoms are, sneezing, lachrymation, frontal headache, nausea, and loss of appetite, with colicky pains, thirst, &c. Among those employed in preparing the paper-hangings more serious symptoms manifest themselves. The irritation of the pigment gives rise to circular patches of ulceration on the alæ of the nose, in the folds of the arm, in the groin and scrotum—in short, wherever dirt tends to lodge. These prove very untractable, except the employment be abandoned. In November, 1861, a young woman died in London from the poisonous effects of arsenite of copper used in dusting wax leaves. The workmen who employ the pigment in its dry state suffer, while those who use it in a moist condition are probably unaffected by it. A simple method for roughly detecting arsenite of copper in these fabrics was published in the Chemical News (vol. 1, p. 12). A small portion of the suspected material is to be put into a test tube with strong ammonia. If a blue tint be produced, a salt of copper is shown to be present. Withdraw the object, and drop a piece of nitrate of silver into the ammonia; if arsenic be there, the nitrate of silver will be covered with a yellow coating of arseniate of silver, which will disappear on stirring. On igniting arsenical paper and allowing it to smoulder, the odor of garlic may be detected in the fumes given off. Another mode in which the noxious effects of arsenic are produced is by the use of bright green tarlatans as ball dresses. One could hardly conceive a more deadly amusement than dancing in an arsenicated dress, sweeping against an arsenicated wall-paper. When both are lightly adherent the arsenic is scattered in showers about the room.
Arsenious Acid (White Oxide of Arsenic, White Arsenic, Arsenic).—This is the preparation of arsenic most frequently used as a poison; the facility with which it used to be procured, its cheapness (twopence an ounce), and the ease with which it may be administered, all tended to recommend it to the murderer or suicide. According to a parliamentary report, the number of fatal cases of poisoning in England in the years 1837, 1838, amounted to 543, of which no less than 186 were caused by arsenic, 185 arising from the use of the arsenious acid, and 1 from orpiment or yellow arsenic.