§ 834. Medicinal and Fatal Dose—Horses.—Cinnabar 14·2 grms, (1⁄2 oz.), calomel 14·2 grms. (1⁄2 oz.) or more, corrosive sublimate ·13 to ·38 grm. (2 to 6 grains), and as much as 1·3 grm. (20 grains) have been given in farcy.
Cattle.—Mercury with chalk 3·8 to 11·6 grms. (1 to 3 drms.), calomel 3·8 to 7·7 grms. (1 to 2 drms.) for worms; ·65 to 1·3 grm. (10 to 20 grains) as an alterative; Ethiops mineral, 7·7 to 15·5 grms. (2 to 4 drms.).
Dogs.—Ethiops or Turpeth mineral ·13 to 1·3 grm. (2 to 20 grains), according to the size.
Fowls.—Mercury and chalk are given in fractions of a grain.
Hogs are also treated with mercury and chalk; the dose usually given does not exceed ·32 grm. (5 grains).
It may be remarked that many of the doses quoted appear very large; the writer cannot but consider that 20 grains of corrosive sublimate administered to a horse would be more likely to kill the animal than to cure the disease.
Man.—Corrosive sublimate has been fatal in a dose so small as ·19 grm. (3 grains); white precipitate has caused dangerous symptoms in doses of from 1·9 to 2·6 grm. (30 to 40 grains); the cyanide of mercury has killed a person in a dose of ·64 grm. (10 grains)—Christison; and Turpeth mineral has proved fatal in doses of 2·6 grms. (40 grains).
Other preparations of mercury have also been fatal, but a doubt has existed as to the precise quantity. Sometimes, also, there is probably a chemical change in the substance, so that it is impossible to state the fatal dose. For example, it is well known that calomel, under the influence of alkaline chlorides, can be converted into the bichloride—a fact which probably explains the extensive corrosive lesions that have been found after death from large doses of calomel.
§ 835. Poisoning by Mercury—Statistics.—In the Registrar-General’s death returns for the ten years ending 1892, it appears that in England the deaths from mercurial poisoning[913] were 40 males, 19 females; of these, 16 males and 18 females were cases of suicide, the remainder were referred to accident.