iodine solution until the liquid is of a deep yellow
colour. The mixture is then cooled, acidified by means of sulphuric
acid, and titrated with decinormal sodium thiosulphate solution. S.B.
Schryver (_Jour, of Soc. Chem. Industry_, 1899, 18, p. 553) adds
excess of sodamide to a solution of the phenol in a suitable solvent,
absorbs the liberated ammonia in an excess of acid, and titrates the
excess of acid. See also C.E. Smith, _Amer. Jour. Pharm._, 1898, 369.

_Pharmacology and Therapeutics_.--Carbolic acid is an efficient
parasiticide, and is largely used in destroying the fungus of ringworm
and of the skin disease known as _pityriasis versicolor_. When a
solution of the strength of about 1 in 20 is applied to the skin it
produces a local anaesthesia which lasts for many hours. If
concentrated, however, it acts as a caustic. It never produces
vesication. The drug is absorbed through the unbroken skin--a very
valuable property in the treatment of such conditions as an incipient
whitlow. A piece of cotton wool soaked in strong carbolic acid will
relieve the pain of dental caries, but is useless in other forms of
toothache. Taken internally, in doses of from one to three grains,
carbolic acid will often relieve obstinate cases of vomiting and has
some value as a gastric antiseptic.

_Toxicology_.--Carbolic acid is distinguished from all other acids
so-called--except oxalic acid and hydrocyanic acid--in that it is a
neurotic poison, having a marked action directly upon the nervous
system. In all cases of carbolic acid poisoning the nervous influence is
seen. If it be absorbed from a surgical dressing there are no irritant
symptoms, but when the acid is swallowed in concentrated form, symptoms
of gastro-intestinal irritation occur. The patient becomes collapsed,
and the skin is cold and clammy. The breathing becomes shallow, the drug
killing, like nearly all neurotic poisons (alcohol, morphia, prussic
acid, &c.), by paralysis of the respiratory centre, and the patient
dying in a state of coma. The condition of the urine is of the utmost
importance, as it is often a clue to the diagnosis, and in surgical
cases may be the first warning that absorption is occurring to an undue
degree. The urine becomes dark green in colour owing to the formation of
various oxidation products such as pyrocatechin. Fifteen grains
constitute an exceedingly dangerous dose for an adult male of average
weight. Other symptoms of undue