the formation of nitriles from potassium cyanide, and of isonitriles from silver cyanide by the assumption that unstable addition products are formed, the nature of which depends on the relative state of unsaturation of the carbon and nitrogen atoms under the varying conditions:-
KNC→KN:C(:C2H5I)→KI+C2H5CN,
AgNC→AgN(:C2H5I)C→AgI+C2H5NC;
that is, when the metal is highly electro-positive the carbon atom is the more unsaturated, the addition takes place on the carbon atom, and nitriles are produced. The same type of reaction occurs when the metal is relatively electro-positive to the added radical, for example, with ethyl isocyanide and acetyl chloride (see above); compare also AgNC→AgN(:Cl·COCH3)C→AgCl+CH3COCN. On the other hand, when there is but little electro-chemical difference between the radical of the cyanide and that of the reacting compound then the nitrogen atom is the more unsaturated element and isonitriles are produced. This explanation also accounts for the formation of nitriles by the diazo reaction, thus:—
C6H5N2Cl+CuNC→CuN:C·Cl·N2·C6H5→CuCl+ N⫶C·N2·C6H5→C6H5→CN+N2.
Detection.—The metallic cyanides may be detected by adding ferrous sulphate, ferric chloride, and hydrochloric acid to their solution, when a precipitate of Prussian blue is produced; if the original solution contains free acid it must be neutralized by caustic potash before the reagents are added. As an alternative test the cyanide may be decomposed by dilute hydrochloric acid, and the liberated hydrocyanic acid absorbed in a little yellow ammonium sulphide. The excess of reagent is removed by evaporation and a small quantity of a ferric salt added, when a deep red colour is produced. Silver nitrate gives a white precipitate with cyanides, soluble in excess of potassium cyanide. The amount of hydrocyanic acid in a solution may be determined by adding excess of caustic potash and a small quantity of an alkaline chloride, and running into the dilute solution standard silver nitrate until a. faint permanent turbidity (of silver chloride) is produced, that is, until the reaction, 2KNC+AgNO3＝KAg(NC)2+KNO3, is completed.
See R. Robine and M. Lengler, The Cyanide Industry, 1906 (Eng. trans. by J. A. Le Clerc); W. Bertelsmann, Die Technologie der Cyanverbindungen, 1906.
Pharmacology, Therapeutics and Toxicology of Hydrocyanic Acid.—The pharmacopoeia preparations of this acid are a 2% solution, which is given in doses of from two to six minims, the tinctura chloroform et morphinae composita, which contains a half-minim of this solution in each ten minims, and the aqua laurocerasi, which owes its virtues to the presence of this acid, and is of inconstant strength, besides being superfluous. The acid is also the active ingredient of the preparations of Virginian Prune, to which the same strictures apply.
The simple cyanides share the properties of the acid, except those of platinum and iron. With these exceptions, the simple cyanides are readily-decomposed even by carbonic acid, free prussic acid being liberated. The double cyanides are innocuous. Hydrocyanic acid is a protoplasmic poison, directly lethal to all living tissues, whether in a. plant or an animal. It is by no means the most powerful poison known, for such an alkaloid as pseud-aconitine, which is ethal in dose of about 1/200 of a grain, is some hundreds of times more toxic, but prussic acid is by far the most rapid poison known, a single inhalation of it producing absolutely instantaneous death. The acid is capable of passing through the unbroken skin, whereupon it instantly paralyses the sensory nerves. It is very rapidly absorbed from raw surfaces and may thereby cause fatal consequences. It is naturally an antiseptic.
The therapeutic applications of the drug are based entirely upon its anaesthetic or anodyne power. A lotion containing ten minims of the dilute acid to an ounce of water and glycerin will relieve itching due to any cause; and is useful in some forms of neuralgia. It must never be employed when the skin is abraded. The diluted acid is used internally to relieve vomiting or gastric pain. It is also added to cough mixtures, when the cough is of the dry, painful kind, which serves no purpose, as nothing is expectorated. Such a cough is relieved by the sedative action on the central nervous system.
Toxicology.—Instantaneous death results from taking the pure acid. The diluted form, in toxic quantities, will cause symptoms usually within a few seconds. The patient is quite unconscious, the eyes are motionless, the pupils dilated, the skin cold and moist, the limbs relaxed, the pulse is slow and barely perceptible, the respiration's very slow and convulsive. Past morlem, the body is livid, and the blood very dark. There may be an odour of prussic acid, but this soon disappears.
Treatment is only rarely of use, owing to the rapidity of the toxic action. The patient who survives half-an-hour will probably recover, as the volatile acid is rapidly excreted by the lungs. The drug kills by paralysing the nervous arrangements of the heart and respiration. The appropriate drug is therefore atropine, which stimulates the respiration and prevents the paralysis of the heart. One-fiftieth of a grain must be immediately injected subcutaneously. The stomach must be washed out and large doses of emetics given as soon as possible. Every second is of consequence. Ammonia shouldbe given by inhalation, and artificial respiration must never be forgotten, as by it the paralysed breathing may be compensated for and the poison excreted. The use of chemical antidotes, such as iron salts, is futile, as the drug has escaped into the blood from the stomach long before they can be administered.
PRUTZ, HANS (1843– ), German historian, son of Robert
Eduard Prutz (1816–1872), the essayist and historian; was born
at Jena on the 20th of May 1843, and was educated at the universities
of Jena and Berlin. In 1865 appeared his monograph on
Henry the Lion, duke of Saxony and Bavaria, which was followed
by three volumes on the emperor Frederick Barbarossa
(Kaiser Friedrich I., Danzig, 1871–1874). Meanwhile from
1863 to 1873 he was teaching in secondary schools. In 1874 he
received a government commission to undertake explorations
in Syria, particularly at Tyre, and as a result he published in
1876 Aus Phönicien, a collection of historical and geographical
sketches. In the same year appeared his first work on the
Crusades, Quellenbeiträge zur Geschichte der Kreuzzüge, and a
series of monographs on the same subject culminated in 1883 in
the notable Kulturgeschichte der Kreuzzüge. Then turning to a
wider theme Prutz contributed to Oncken's university history
the two volumes on the political history of Europe during the
middle ages (Staatengeschichte des Abendlandes im Mittelalter,
Berlin, 1885–1887). In 1888 he reverted to a subject which he
had touched upon in his Geheimlehre uud Geheimstatuten des
Tempelherrenordens (Danzig, 1879), and wrote the history of the
rise and fall of the Templars (Entwickelung und Untergang des
Tempelherrenordens), which is noticed in the article Templars.
His Preussische Geschichte (4 vols., Stuttgart, 1899–1902), which
is perhaps his most notable work, is an attempt to apply
scientific rather than patriotic canons to a subject which has
been mainly in the hands of historians with a patriotic bias.
He also wrote Aus des Grossen Kurfürsten letzten Jahren
(Berlin, 1897) and Bismarcks Bildung, ihre Quellen und ihre
Äusserungen (Berlin, 1904). In 1902 Prutz resigned the chair
of history in the university of Königsberg, which he had held
since 1877, and took up his residence at Munich.
PRUTZ, ROBERT EDUARD (1816–1872), German poet and
prose writer, was born at Stettin on the 30th of May 1816. He studied philology, philosophy and history at Berlin, Breslau and Halle, and in the last-named became associated, after taking his degree, with Arnold Ruge in the publication of the Hallesche Jahrbücher. Subjected on account of his advanced political views to police surveillance, he removed to Jena, where, on the strength of an excellent monograph, Der Göttinger Dichterbund (1841), he hoped to obtain an academic appointment.
He was, however, expelled from the town for offending against the press laws, and it was not until 1846 that he received permission to lecture in Berlin. From 1849 to 1859 he was extra-ordinary professor of literature at Halle, but retired in 1859 to Stettin, where he died on the 21st of June 1872.
Prutz belonged to the group of political poets who dominated German literature between 1841 and 1848; hispoems are more conspicuous for their liberal tendency than their poetry. Among them may be mentioned Ein Märchen (1841); Gedichte (1841); Aus der Heimat (1858); Neue Gedichte (1860); Herbstrosen (1865); Buch der Liebe (1869). Among his novels are noteworthy, Das Engelchen (1851) and Der Musikauteuturm (1855); Much more important are his contributions to literary history and criticism: Vorlesungen über die Geschichte des deutschen Theaters (1847); Ludwig Holberg (1857); Die deutsche Literatur der Gegenwart (1859), and Menschen und Bücher (1862). Prutz also Wrote some dramas of little merit.
See R. von Gottschall, in Unsere Zeit (1872).
PRYNNE, WILLIAM (1600–1669), English parliamentarian, son of Thomas Prynne by Marie Sherston, was born at Swainswick near Bath in 1600. He was educated at Bath Grammar School, matriculated at Oriel College, Oxford, in 1618, obtained his B.A. in 1621, was admitted a student of Lincoln's Inn the same year, and was called to the Bar in 1628. He was Puritan
