Recurrent colic is as a rule less severe than the simple acute form, but may last for several weeks, clearing up for three or four days at a time and then recurring with little diminution in violence from the first attack. Such cases are probably due to the gradual excretion of lead by the intestine, and should be treated on this supposition. In the continued or chronic colic the pain may persist for as long as two months, during the whole of which time the patient complains of uneasiness and even constant pain in the lower part of the abdomen, which becomes considerably worse after each evacuation, and almost invariably is associated with exceedingly obstinate constipation. It is this type of case that olive-oil or liquid paraffin relieves, while in the acuter forms drastic purgatives such as castor-oil, croton-oil, or pulv. jalapæ comp. may be administered. For the treatment of pain in colic one of the various vaso-dilators should be used, as, in addition to the spasm of the intestine, a very considerable vaso-constriction of the whole of the vessels in the mesenteric area occurs. Amyl nitrite gives immediate relief, but the effect passes off somewhat rapidly, whilst scopolamine, although taking somewhat longer to act, is better for continuous use, as its action is longer maintained. Sodium nitrite, liquor trinitrini, and antipyrin are also of use. Atropin may be used, but it is perhaps better given in conjunction with magnesium sulphate. Whatever form of purgative is given, some form of anodyne should be combined. Drissole and Tanquerel[3] are said to have obtained excellent results with croton-oil; one drop is given, followed seven or eight hours later by another, and then by an enema of 2 pints of normal saline. After two or three days the croton-oil may be again given, one drop at a time each day. In addition, Tanquerel made use of belladonna and opium together, finding that their combined action was better than that of opium alone, as the physiological effect of belladonna probably assists in preventing the intestinal cramp. Hoffmann[4] recommends the use of olive-oil and opium, giving 3 to 4 ounces of olive-oil. He says that this relieves the spasm of the pylorus, and is of particular use where severe vomiting is associated with the colic. This use of olive-oil, first suggested by Hoffmann in 1760, and revived by Weill and Duplant[5] in 1902, is somewhat interesting, in view of the modern tendency to administer paraffinum liquidum in the treatment of chronic constipation.