MERCURIC THYMOLATE.-METALDEHYD.

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Administration.-Thymolacetate of mercury is given internally in pill form, hypodermatically, or in intramuscular injections, in doses of from to grain (0.005 to 0.010 gramme).

MERCURIC THYMOLATE.

Another compound of mercury, having a formula of (C10H130)Hg-HgNO3.

Physical Properties.-This drug when pure is odorless and tasteless, but is liable on exposure to acquire a slight odor of thymol.

Therapeutic Applications.-Thymolate of mercury has been particularly recommended in the treatment of syphilis.

Administration.—The dose is about the same as that of the thymolacetate.1

METALDEHYD.

The action of polymerizing agents upon aldehyd at a temperature below 32° F. (0° C.) gives rise to the formation of metaldehyd; it may also be obtained by passing hydrochloric acid vapors through acetic aldehyd and then freezing the mixture. It is a body represented by the formula (C2H,O)

Physical Properties.-This drug is a white crystalline substance made up of needles or tetragonal prisms which sublime between 233.6° and 239° F. (112° and 115° C.) without melting.

1 Many other combinations of mercury have of late been brought to the notice of the profession, chief among which may be mentioned the benzoate (CH COO),Hg,H,O, a crystalline body, tasteless, odorless, and soluble in hot water and alcohol; the formamidate; the naphtholate, an odorless lemon-yellow powder containing about 30 per cent. of mercury; the naphtholacetate, a white crystalline substance; the oxycyanide, Hg,O(CN),; the peptonate, a yellowish liquid with a saline and slightly metallic taste; the tannate, occurring in brownish-green odorless and tasteless scales; and the thymolsulphate. All these salts have been recommended in the treatment of syphilis. Other mercuric compounds will be described under other names.

Solubility.-Metaldehyd is readily soluble in hot alcohol and ether, but insoluble in water.

Therapeutic Applications.-This medicament possesses hypnotic virtues similar to those of paraldehyd, but its use in practical medicine has not been very extensive.

Administration.-The dose of metaldehyd may be said to be more or less the same as that of paraldehyd.

METAMIDOPHENYLPARAMETHOXYCHINOLIN. Therapeutic Applications.-This drug has recently been recommended as an antiperiodic in the treatment of malarial diseases, in which it is said to equal quinine.

Administration.-It has been given in doses of from 3 to 7 grains (0.25 to 0.50 gramme).

METHACETIN.

This name is applied to para-acetanisidin or para-oxymethylacetanilid, or acetyl-methyl-para-amido-phenol, being thus chemically constituted: CH,.OCH, NHCH,CO.

Physical Properties.-Methacetin occurs in crystalline scales, almost colorless or somewhat reddish, and without taste. It melts at 260.6° F. (127° C.).

Solubility. This drug is readily soluble in alcohol, chloroform, glycerin, and warm fatty oils; also in water in the proportion of 1 to 260 parts.

Physiological Action.-Large doses cause death preceded by convulsions. It is said to reduce the bodily temperature by diminishing both heat-production and heat-distribution.

Therapeutic Applications.-Methacetin has been much lauded as an antiseptic and analgesic. It is especially suitable in the treatment of febrile diseases of children. This remedy has proved to be of value in rheumatic and tubercular affections. It has given good results in the pyrexia of phthisis, in which it is said to

METHOXYCAFFEINE.--METHYLAL.

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be better administered early in the afternoon when given once daily.

Administration.-Methacetin is given in doses of from 2 to 5 grains (0.12 to 0.3 gramme), and is best administered in mucilage or in cachets.

Toxicology.-Methacetin is apt to depress the heart, and sometimes collapse accompanied or preceded by profuse sweating follows the ingestion of the drug.

METHOXYCAFFEINE.

A derivative of caffeine, and found also in other allied plants. Its chemical composition is C,H,(OCH,)H1O2. Physical Properties. This drug appears in white crystalline needles having a melting-point of 350.6° F. (177° C.).

Therapeutic Applications.-Methoxycaffeine has been found beneficial in cases of migraine and in neuralgias. It is even said to possess anæsthetic properties superior to those of cocaine, especially when it is injected hypodermatically.

Administration.—The dose of the medicament is about 4 grains (0.24 gramme).

METHYLAL.

Methylal is also designated by the term methyenmethylether, and results from the interaction of methylic alcohol, binoxide of manganese, and sulphuric acid. It is represented thus: CH2(OCH3)2.

Physical Properties.-Methylal is a highly volatile. liquid having a penetrating ethereal odor. Its meltingpoint is 107.6° F. (42° C.), and it has a sp. gr. of 0.855.

Solubility. This remedy is soluble in alcohol and in ether, in fatty and ethereal oils, and in water in the proportion of 1 to 13 parts.

Physiological Action.-This drug diminishes reflex action and the irritability of the cerebral cortex. In sufficiently large amounts it acts upon the cardiac ganglia

and muscle, causing increased rate of the pulse and a reduction of the blood-pressure and the bodily temperature.

Therapeutic Applications.-Methylal has been used. with marked effect as a hypnotic, and particularly in the treatment of insanity and the insomnia of delirium tremens. It has also been employed as a local anæsthetic.

Administration.-The dose of methylal varies from 15 to 30 minims (1 to 2 grammes), and even as high as 2 drachms (8 grammes).

METHYL CHLORIDE.

Other names are applied to this substance, such as chlormethyl and monochlormethane. It is obtained by the action of hydrochloric acid upon alcohol. Its chemical composition is represented as CH,Cl.

Physical Properties.-Chloride of methyl is a colorless gas with an odor resembling that of ether and chloIt is somewhat inflammable, and burns with a greenish flame. It liquifies at -13° F. (-25° C.), and at 9.6 F. (-23.7° C.) has a sp. gr. of 0.9915. It boils at -5.8° F. (--21° C.).

Solubility. Chlormethyl is readily soluble in ether and in chloroform, less so in alcohol; in water, in onefourth its volume:

Therapeutic Applications.-The most marked properties of this drug are those of an anæsthetic, and as such it has been employed in minor surgical operations. It has rendered good service in the local treatment of neuralgia, spinal pains, pruritus, etc.

Administration.-This remedy is best applied in the form of a spray.

METHYLENE BLUE.

This substance is classed as one of the aniline dyes, and is also called tetramethylthionin. Its chemical formula is represented as follows:

METHYLENE CHLORIDE.

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C6H3-N(CH3)2

N

CH2 N(CH3)2Cl.

Physical Properties.-This drug appears as a bluish powder composed of scaly crystals, dark green in transverse fracture, and of a bronze-like tinge.

Solubility.-Methylene blue is somewhat soluble in water, and more so when this vehicle contains alcohol.

Therapeutic Applications.-This new remedy has been largely used with apparent success as an anodyne in the treatment of rheumatic and neuralgic disorders, and likewise in pulmonary tuberculosis and scrofula. Quite recently it has been highly recommended as an antiperiodic, particularly in cases in which quinine has failed, and in the local treatment of diphtheria.

Administration.-The dose varies from 11⁄2 to 8 grains (0.09 to 0.52 gramme), and is best given in wafers or capsules. Hypodermatically it can be injected in doses of from 1 to 1 grain (0.02 to 0.06 gramme).

METHYLENE CHLORIDE.

This drug, which is also known by the name of dichlormethane, is obtained by the action of chlorine on monochlormethane or by reducing chloroform by zinc and hydrochloric acid. It has the composition CH,Cl2.

Physical Properties.-Chloride of methylene is a colorless liquid with an odor resembling that of chloroform, Its sp. gr. at 59° F. (15° C.) is 13.6; it melts at 106° F. (41.6° C.).

Solubility. This drug is soluble in alcohol and in

ether.

Therapeutic Applications.-Methylene chloride has been recommended as a substitute for chloroform, but is now chiefly employed as a local anesthetic.