1771 T. Smollett Humphry Clinker III. 149 And mirth he has a particular knack in extracting from his guests, let their humour be never so caustic or refractory.

1817 W. Scott Rob Roy I. iv. 82 His shrewd, caustic, and somewhat satirical remarks.

1842 T. B. Macaulay Frederic the Great in Ess. (1877) 677 Those who smarted under his caustic jokes.

1876 ‘G. Eliot’ Daniel Deronda I. ii. xviii. 361 Well, ma, I think you are more caustic than Amy.

1728 E. Chambers Cycl. Caustic Curve, in the higher Geometry, a Curve form'd by the Concourse, or Coincidence of the Rays of Light reflected, or refracted from some other Curve.

1869 J. Tyndall Notes 9 Lect. 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.

1869 J. Tyndall Notes 9 Lect. on Light §166 Spherical lenses have their caustic curves and surfaces formed by the intersection of the refracted rays.

1738 E. Chambers Cycl. (ed. 2) (at cited word) Every curve has its twofold Caustic.

1743 Philos. Trans. 1742–3 (Royal Soc.) 42 343 In the next place, the Caustics, by Reflexion and Refraction, are determined.

1869 J. Tyndall Notes 9 Lect. 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).

1800 Med. & Physical Jrnl. 3 480 Caustic bougies, applied to the urethra under pretence of removing strictures.

1805 Med. & Physical Jrnl. 14 474 The superiority of the caustic over the common bougie.

1926 J. M. Black Flora S. Austral. iii. 463 S[arcostemma] australe, R. Br. Milk Bush; Tableland Caustic Bush.

1887 F. M. Bailey & P. R. Gordon Plants reputed Poisonous 79 Euphorbia Drummondii, Caustic Creeper... This weed is unquestionably poisonous to sheep.

1889 J. H. Maiden Useful Native Plants Austral. 127 Euphorbia Drummondii... Called ‘Caustic Creeper’ in Queensland. Called ‘Milk Plant’ and ‘Pox Plant’ about Bourke. This weed is unquestionably poisonous to sheep.

1887 F. M. Bailey & P. R. Gordon Plants reputed Poisonous 43 Sarcostemma Australe. Known as ‘Caustic plant’ or ‘Caustic vine’ in Queensland.

1898 E. E. Morris Austral. Eng. 84 Caustic-Plant, or Caustic-Vine... Cattle and sheep are poisoned by it.

1922 Jrnl. Proc. Royal Soc. New S. Wales 56 183 This plant [sc. Sarcostemma australe], which occurs in all the Australian States except Victoria and Tasmania, is known as ‘Caustic Vine’, or ‘Caustic Plant’.

1887 F. M. Bailey & P. R. Gordon Plants reputed Poisonous 43 Sarcostemma Australe. Known as ‘Caustic plant’ or ‘Caustic vine’ in Queensland.

1898 E. E. Morris Austral. Eng. 84 Caustic-Plant, or Caustic-Vine... Cattle and sheep are poisoned by it.

1922 Jrnl. Proc. Royal Soc. New S. Wales 56 183 This plant [sc. Sarcostemma australe], which occurs in all the Australian States except Victoria and Tasmania, is known as ‘Caustic Vine’, or ‘Caustic Plant’.

1954 W. E. Blackall W. Austral. Wildflowers 263 E[uphorbia] Drummondii. Caustic-weed.

1858 Med. Times & Gaz. 23 Oct. 428/2 The caustic is cut into little pointed laths, very like our vaccine points. They are not placed circularly around the base of the tumour, but parallel to each other over the whole of its free surface, so that its interior consists of a kind of bundle of caustic arrows, between the interstices of which the tissues are reduced to great thinness, and are rapidly destroyed.]

1860 R. Druitt Princ. & Pract. Mod. Surg. (rev ed.) p. xvii Introduction of conical caustic arrows for circular cauterization.

1879 St. George's Hosp. Rep. 9 384 A tumour around the anus was removed by the insertion of caustic arrows.

1890 J. S. Billings National Med. Dict. I Caustic arrows,..small, pointed cylinders or cones made of chloride-of-zinc paste or other caustics, intended for introduction into the substance of morbid growths.

1911 Amer. Jrnl. Clin. Med. 18 1166/1 All of us have seen instances of women with a tumor in the breast..who have suffered the tortures of the damned for weeks and weeks after the use of Vienna paste or plasters or caustic ‘arrows’.

1852 E. C. Gaskell Let. 1 Oct. (1966) 852 My right arm is very bad & Mr. Mellor comes to see it & caustics it.

1870 Lady Amberley Diary 22 Nov. in Amberley Papers (1937) II. xiii. 382 My throat was very bad to-day, Mr. Audland causticed it & made me stay in bed.

1888 Mrs. H. Ward Robert Elsmere I. ii. xii. 333 I causticked all the diphtheritic throats..with my own hand.