Contractions. - Caus. Can.

This is a preparation peculiar to Homoeopathy, and hence must be prepared exactly according to Hahnemann's directions, which are as follows: -

"Take a piece of recently burnt lime, weighing about 2 pounds, immerse it for a minute in a vessel full of distilled water, and then lay it in a dry cup, where it soon becomes pulverized, giving out much heat and a peculiar odour, called the vapour of lime. Of this fine powder you take 2 ounces, and place it in the mortar which had been previously warmed, and then mix with a solution of 2 ounces of the Bi-sulphate of Potash in 2 ounces of boiling hot water, the Potash, before being dissolved, having been exposed to a red heat, melted, cooled again, and then pulverized. This thickish preparation is inserted into a retort, to the open end of which the receiver, which ought to be dipped in water to half its height, is hermetically fastened. The liquid is distilled over by gradually approaching a coal fire to the retort, and until the preparation is perfectly dry. The liquid in the receiver is about 1 ounce and a half, as clear as water, and containing the Causticum in a concentrated form, which smells like the lye obtained from Potash, and has an astringent and burning taste on the back part of the tongue. Its freezing-point is below that of water; it promotes the putrefaction of animal substances which are placed in it; with the Salts of Baryta it gives no trace of Sulphuric Acid, nor any trace of lime-earth with the Oxalate of Ammonium." In order to preserve this solution, it is necessary to add 5 per cent. of rectified spirit.

It will be observed that Hahnemann says nothing about the presence or absence of Potash; he merely says that neither Sulphuric Acid nor Lime are to be found in it when properly prepared. In the 24th vol. of the " British Journal of Homoeopathy" there is a paper by Dr. Black, wherein he states that all the specimens he had analyzed were found to contain Potash, and in fact he believes that it is a very weak solution of Caustic Potash, and he proposes that this should be substituted for Causticum in future. It might be well worth while to prove Caustic Potash, and ascertain whether its effects corresponded with those of Causticum, and if found to do so, the one could be substituted for the other; but until such proving shall have been made, it is much safer to adhere to Hahnemann's preparation, especially when prescribing the high dilutions.

Preparation. - Attenuations should be made with rectified spirit. What is called mother tincture, however, in this case is of unknown strength.

Reference to Horn. Proving. - Chr. Kr., III.

Proper forms for dispensing. - φ, Tincture only. lx and upwards, Tincture, Pilules, or Globules.

Cepa. Vide Allium Cepa, p. 56.