"Take of bruised nux vomica, two pounds; rectified spirit, three gallons; diluted sulphuric acid, magnesia, solution of ammonia, of each, a sufficient quantity. Boil the bruised nux vomica with a gallon of the spirit for an hour, in a retort, to which a receiver is adapted. Decant the liquor, and boil the residue again, and a third time, with another gallon of spirit and the spirit recently distilled, and pour off the liquor. Press the nux vomica, and the fluid obtained being mixed with the other liquors, distil the spirit. Evaporate the residue to the consistence of an extract. Dissolve this in cold water, and strain. Evaporate the solution, with a gentle heat, to the consistence of a syrup. Add to this, whilst it is hot, the magnesia, in small quantities at a time, to saturation, stirring them together. Set the mixture apart for two days, then decant the supernatant fluid. Press the residue in a linen cloth. Boil it in spirit, then strain and distil the spirit. Add to the residue a little diluted sulphuric acid mixed with water, and macerate with a gentle heat. Set it aside for twenty-four hours, that crystals may form. Press and dissolve them. Finally, to these, dissolved in water, add ammonia, stirring frequently to favour the precipitation of the strychnia.

Afterwards dissolve these, and set the solution aside that crystals may be produced."

Strychnia and brucia exist in nux vomica in the form of igasurates; in the above process these salts are taken up by the alcohol. The addition of the cold water to the extract deprives it of a fatty matter: and the magnesia being added to the solution freed from this matter, decomposes the igasurate and leaves the strychnia, which is very insoluble, to precipitate. This precipitate is impure strychnia, and is readily taken up by the spirit; the residue, after the distillation of the spirit, being converted by the sulphuric acid into sulphate of strychnia: this salt is decomposed by the ammonia, which forms a soluble sulphate, and the strychnia is precipitated. The crystals formed in the alcoholic solution always contain some brucia, which, however, can be removed by maceration in diluted alcohol.

Qualities.-Strychnia crystallizes in minute quadrilateral crystals, inodorous, and impressing an excessively bitter taste upon the palate; so bitter indeed, as to communicate the taste to 600,000 times their weight of water. It requires 6000 parts of water at 60°, and 2500 parts at 212°, for solution. It is insoluble in very strong alcohol and in aether; but it dissolves readily in alcohol of a sp. gr. 850. It has a decided alkaline reaction, and forms neutral salts with the acids. Owing to the brucia which it generally contains, it strikes a blood red with nitric acid; but, when pure, it forms a pale straw-coloured solution. Its constituents are 180 parts of carbon, 16 of hydrogen, 24 of oxygen, and 14 of nitrogen, in 100 parts, or it consists of 30 eq. of carbon = 183.6 +16 of hydrogen = 16+3 of oxygen =24+1 of nitrogen, = 14.15, making the equivalent 237.75.

Medical properties and uses. - Strychnia is a tonic, a powerful excitant, and an acro-narcotic poison, operating specially upon the motor tract, and in a less degree upon the sensitive tract of the spinal cord. This is demonstrated by the fact that the division of the cord near the occiput, or even decapitation, does not interfere with its operation. In large doses, or in moderate doses long continued, it causes tetanic spasms, and such a rigidity of the respiratory muscles, as to produce fatal asphyxia; a property which has been taken advantage of to restore the nervous energy in paraplegia and partial paralysis, especially that caused by carbonate of lead. Its employment as a remedy in paraplegia was suggested by M. Fouquier, and its efficacy in this and other forms of palsy has been verified by Dr. Bardeley, Majendie, myself, and many others. Owing to the insolubility of strychnia, it is very uncertain in its operation; being either almost inert, or too active, according to the quantity of acid present in the stomach.

I have, therefore, found it most efficacious when administered in the form of an acetate, which is readily formed by dissolving gr. j. of the alkali in f 3j. of distilled vinegar; so that six minims contain one tenth of a grain of strychnia, the proper dose to commence with. In some habits I have seen one sixteenth of a grain produce tetanic twitchings; whilst in others I have given gr. iss. without the smallest obvious effect. As soon as the tetanic twitchings become so severe as to affect the breathing, the medicine should be discontinued, and after some days again recommenced in smaller doses, if it be necessary to persist in its use. In very minute doses, strychnia operates as a tonic, and has been beneficially employed in pyrosis, passive diarrhoea, and leucorrhoea.

I have employed strychnia sprinkled on blistered surfaces, with advantage, in incipient amaurosis depending on simple atony of the optic nerve, and in partial paralysis: half a grain mixed with grs. ijss. of refined sugar is a proper quantity in such cases.