a. and sb. [ad. L. caustic-us a. Gr. καυστικός capable of burning, caustic, f. καυστ-ός burnt, burnable, f. και- (future καυσ-) to burn. Cf. F. caustique.]
A. adj. 1. Burning, corrosive, destructive of organic tissue.
1555. Eden, Decades W. Ind. (Arb.), 229. Albeit the water of the sea haue a certeyne caustike qualitie ageynst poyson.
1563. T. Gale, Antidot., I. vii. 5. Causticke medicynes which doe remoue, and take away fylthines in vlcers.
1605. Timme, Quersit., I. vi. 25. Causticke and burning simples.
1727. Bradley, Fam. Dict., I. s.v. Gourdy legs, This Stone … from its … caustick or burning Quality, alone destroys Warts.
1863–72. Watts, Chem. Dict., I. 818. In the old language of surgery, caustics were divided into the actual, such as red-hot iron and moxa, and the potential, such as strong alkalis, acids, nitrate of silver.
b. Caustic bougie: a bougie armed with a piece of caustic.
1800. Med. Jrnl., III. 480. Caustic bougies, applied to the urethra under pretence of removing strictures. Ibid. (1805), XIV. 474. The superiority of the caustic over the common bougie.
c. Chem. Caustic alkali: a name given to the hydrates of potassium and sodium, called caustic potash (KHO) and caustic soda (NaHO), respectively; caustic volatile alkali or caustic ammonia, ammonia as a gas or in solution; caustic lime, quick lime (CaO).
1774. Goldsm., Nat. Hist. (1776), VIII. 143. These flies, thus dried … yield a great deal of volatile caustic-salt.
1791. Hamilton, Berthollet’s Dyeing, I. I. I. v. 80. Caustic alkali tinges the infusion of galls of a dark red.
1811. A. T. Thomson, Lond. Disp. (1818), 564. Take … water of caustic kali, nine fluid ounces.
1813. Sir H. Davy, Agric. Chem. (1814), 21. As a cement, lime applied in its caustic state acquires its hardness and durability, by absorbing the aerial … acid.
1845. Todd & Bowman, Phys. Anat., I. 102. Add solution of caustic ammonia.
1869. Roscoe, Elem. Chem., 200. Potassium hydroxide or Caustic potash … is a white substance soluble in half its weight of water, and acts as a powerful cautery, destroying the skin.
1876. Harley, Mat. Med., 147. Caustic Soda.
d. gen. Burning. (rare.)
1863. Possibil. of Creation, 148. At the tops of mountains … the sun’s rays are capable of producing very caustic results.
2. fig. That makes the mind to smart: said of language, wit, humor, and, by extension, of persons; sharp, bitter, cutting, biting, sarcastic.
[Not in Johnson 1755.]
1771. Smollett, Humph. Cl. (1793), II. 167 (L.). And mirth he has a particular knack in extracting from his guests, let their humour be ever so caustic or refractory.
1818. Scott, Rob Roy, iv. His shrewd, caustic, and somewhat satirical remarks.
1842. Macaulay, Fredk. Gt., Ess. (1877), 677. Those who smarted under his caustic jokes.
1876. Geo. Eliot, Dan. Der., II. xviii. 147. Well, ma, I think you are more caustic than Amy.
3. Math. Epithet of a curved surface formed by the ultimate intersection of luminous rays proceeding from a single point and reflected or refracted from a curved surface; also of the curve formed by a plane section of a caustic surface. A caustic by reflexion is called a catacaustic, that by refraction a diacaustic. So caustic line, surface.
[So called because the intensity of the light, and consequently of the heat, is in general greater at a point on this surface than at neighboring points not on it, and at special points may become sufficiently intense to initiate combustion in a body there placed. The focus of a concave mirror is the cusp of its caustic for incident parallel rays.]
1727–51. Chambers, Cycl., Caustic curve, in the higher geometry, a curve formed by the concourse or coincidence of the rays of light reflected or refracted from some other curve.
1869. Tyndall, Notes on Light, § 101. The interior surface of a common drinking-glass is a curved reflector. Let the glass be nearly filled with milk, and a lighted candle placed beside it, a caustic curve will be drawn on the surface of the milk. Ibid., § 166. Spherical lenses have their caustic curves and surfaces formed by the intersection of the refracted rays.
B. sb.
1. Med. A substance that burns and destroys living tissue when brought in contact with it. Common or Lunar caustic: nitrate of silver prepared in sticks for surgical use.
1582. Hester, Secr. Phiorav., I. vii. 8. Costicke … beeyng laid on the sore doeth mortefie it.
c. 1600. B. Jonson, Elegy Lady Pawlet, Wks. 1640 II. 251 (R.).
| Stick on your Cupping-glasses, feare not, put | |
| Your hottest Causticks to, burne, lance, or cut. |
1722. De Foe, Plague (1884), 11. They burnt them with Causticks.
1771. Smollett, Humph. Cl. (1793), I. 32 (L.). He applied a caustic to the wart.
1800. Med. Jrnl., III. 290. The application of lunar caustic to strictures.
1879. Harlan, Eyesight, v. 52. Quick-lime acts as a powerful caustic.
b. fig.
1635. Austin, Medit., 197. With his Causticks of Repentance; he (charitably) burnt out, and purged the corruptions of Mens consciences.
1817. Scott, Wav., xx. Pride … applies its caustic as an useful though severe remedy.
1825. L. Hunt, Bacchus in Tuscany, 41.
| I should like to see a snake | |
| Get up in August out of a brake, | |
| And fasten with all his teeth and caustic | |
| Upon that sordid villain of a rustic. |
2. Math. = Caustic curve or surface: cf. A. 3.
1727–51. Chambers, Cycl., s.v., Every curve has its twofold caustic.
1743. Phil. Trans., XLII. 343. In the next place, the Caustics, by Reflexion and Refraction, are determined.
1869. Tyndall, Notes on Light, § 100. When a large fraction of the spherical surface is employed as a mirror, the rays are not all collected to a point; their intersections … form a luminous surface … called a caustic (German, Brennfläche).
