PICOT. 4 2(1 p(l. 1888), liis best work, twice winner of the tiohert prize; />« riformc judiciare ( ISSl ) ;_{"»! clcroir social rt Irs hx/cmoits d'oiinirrs (1855) ; J'aci/icalinn rrligictise (1892) ; and Dt^ccnlralisii- tioii (I xis dilJcnnls aspects (18'.t7). PICPUS (pfk'pys') SOCIETY. The name eonimonlv used for a religious coinniunity in the Konian Catholic Church ollicially styled tlie Con- grefjation of the Sacred Hearts of .Jesus and .Mary an<l of the Perpetual Adoration. It was founded in 1805 hy I'ierre .loscpli Condrin and conlirnied by Pius VII. in 1817. Its mother house was in the Rue Picpus in I'aris, wlience the coIloc|uial name. The society devotes itself to missionary work, es- pecially in Eastern Oceania and South America. Consult Keller, J,fs congregations religieuscs en France (Paris, 1880). PICRIC ACID ( from Gk. TiKp6s, pihro/), bit- ter ) , or ( ah.v/.otic Acid, C„H, ( XOj ) ^Otl. One of the first organic dyes that have been prepared by artificial processes. It is derived from car- bolic acid, or phenol, by the action of nitric acid, and is therefore called also trinitrocarlnilic acid or trinitrophcnol. It is best prepared by dissolvinf; carbolic acid in strong sulphuric acid and gradually adding nitric acid; after the vio- lent action has .subsided, the mi.vturc is kept for about two hours at a gentle heat, so as to com- plete the reaction. Picric acid sejiarates out in crystalline form from the solution thus obtained, aiiil may be purified by crystallization from hot water, in which it is moderately soluble. The acid is also formed by the action of nitric acid on many organic products, such as wool, leather, silk, indigo, resins, etc. While it is but sparingly soluble in cold water, it readily dissolves in organic licpiids like ordinary ajcohol, etiu'r, benzene, etc. Its solutions have a .strongly bitter taste and stain the skin as well as wool and silk a bright yellow. Formerly picric acid was much used as a dye. Since vegetable fibres are not colored by it, it may be used to detect cotton mixed in with wool. .-t ])resent picric acid is used extensively for the manufactvirc of certain ex- plosives. Tlie acid itself burns quietly if ignited: but its alkali derivatives, the picratcs of soditim, potassium, and ammonium, explode when heated, with great violence. It is mostly these deriva- tives of picric acid that are employed in the manufacture of exi)losives. The explosive known as mrlinilr. however, consists mainly of the free acid. Fornu'riy the acid was largely used in the manufacture of smokeless powder. Picric acid is said to have been employed also as a substitute for hops in the manufacture of beer. In France the acid is commonly used as a remedy for luirns, as it is believed to prevent the formation of blisters. A small quantity of the acid is dis- solved in a little alcohol, and the solution is di- luted with a large amount of cold water; the solution is constantly applied to the burned part until the smarting pain has ceased. In organic chemistry picric acid is classed with the phenols, being a benzene derivative containing the hydroxyl group (OH). Unlike most other phenols, however, it is more strongly acid than carbonic acid, from the combinations of which (the carbonates) it is capable of taking away the alkali metals, to form picrates. These strong- ly acid properties of picric acid ( trinitrophenol ) are due to the presence of nitro-groups (NO.) in its molecule. PICTONES. PICROTOXIN (from Gk. jnKpis. pikros. bit- ter + To^iKov, l(i.rilcun, poison, originally that in which arrows were dipped, neu. sg. of to{ik65, loxilcos, relating to a bow, from rd^oy, laxon, bow), C,aH„0,3. The active poi.sonous principle contained in the seeds of Anamirta paniculata, which grows in the Fast Indies. It may be ob- tained from the seeds by extraction with hot alcohol and may be purified by crystallization. The .substance is extremely poisonous, one-third of a grain being sufhcient, when introduced into the stomach of a cat, to produce tetanic con- vdsi(]ns and death in a few minutes. It is some- times used externally as a parasiticide, and in- ternally to check night-sweating in phthisis. PICTET, pek'tft', Raoul (1842—). A Swiss physicist and chemist. He was born at Geneva and served as professor in the university of that city. He has devoted himself largely to prob- lems involving the production of low tempera- tures and the liipiefaction and solidification of gases. ( See LiQi El ACTio.v OF (Jases.) By using extreme cold and pressure he ascertained in 1877 that o.ygen, nitrogen, and hydrogen could be li(|Ueficd, making tiiis discovery about the same time as Cailletet (q.v.) in Paris, who employed an altogi'ther ditl'erent method. Pictct is the author of Mimoire sur la. liquefaction de I'oxy- yvnc. la li(jiiefaeti(in el la solidification dc ihy- droginc et sur Ics thiories des changements des corps (1878); t^ijnthesc dc la chaleur (1879); Xouvelles machines frigorif!(]ues basces siir I'em- ploi dc plienomenes phi/nieochimiques (1895); Elude critique du malerialisme et du spirilual- isiiie par la phi/sique cxpcrimentatc { 1890) ; l/ac<:-tylene (IS'.W) ; and Lc carbide (189ti). PIC'TON, Sir Thomas (1758-1815). A Brit- ish general, born at Poyston, Pembrokeshire. In 1794 he went to the West Indies. He distin- guished himself in the taking of Saint Licia and Saint Vincent from the French, and Trinidad from the Spaniards, and was made Military Gov- ernor of Trinidad in 1797. He restorf;(l order there, and made many imi)rovemcnts, and in 1801 was made brigadier-general and Civil (Jovernor of the island. The severity of his rule caused complaint and he was superseded in 180.S, but was made commandant at Tobago. He was re- called to England to answer charges against his Trinidad administration, but was honorably ac- quitted and as major-general (1808) went to serve at Flushing. He commanded the Third Division under Wellington, and was with him throughout the Peninsular campaigns, and fought in all the lea<ling battles. He was promoted to the rank of lieutenant-general in 1S13, joined Wellington again in the Netherlands, and was killed in the battle of Waterloo, while leading bis brigade. PICTONES, jiik'ton-ez, or PICTA'VI. An ancient trilic in Gaul whose name survives in Poitiers, the capital of the Department of Vicnne. They are mentioned by Caesar with the Scnones, Parisii, Carduci. Turones, Aulerci, and Lcmo- viei in the combination against the Romans organized by Vercingetorix. The chief inter- est in them is the belief that they were Ibe- rians and probably blood kindred of the Picts in Scotland. On the strength of this connection and resemblance in physical characteristics, Rhys, an eminent authority, applies the title Ihero-
