A dispensatory, or commentary on the phgarmacopoeias of Great Britain.

  • Christison, Robert, Sir, 1797-1882.
Date:
1848
Catalogue details

Licence: Public Domain Mark

Credit: A dispensatory, or commentary on the phgarmacopoeias of Great Britain. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    The material which supplies the volatile oil is in general simply mixed with the water in a state of fine division; and this is probably the best mode where heat is used in such way as to exclude the risk of empyreuma. If it does not require to be finely divided, as in the case of fresh leaves and flowers, it may be put conveniently into a net-bag; which is suspended in the middle of the still, and may be withdrawn with facility when its contents are exhausted. Some manufacturers use, not water, but steam for obtaining distilled-waters: That is, the material io be distilled-is spread over a fine gauze partition or a plate per- forated with numerous small holes, and steam is driven through the mass. When the vegetable substance to be exhausted is a bark, wood, or other solid matter, it must be reduced to a state of moderately fine division. But this is not generally necessary in the case of leaves or flowers, because boiling water breaks down the cells in which the volatile oil is contained. When leaves however are thick and leathery, as in the instance of the cherry-laurel, the process is facilitated by chopping them down; and in most cases, where leaves are large, it is difficult to get a sufficient quantity into the still without cutting them into pieces. In preparing the finer kinds of distilled waters, it is necessary to clean the materials care- fully, to remove all decayed leaves or flowers, or those infested by insects, and sometimes also to separate the leaf-stalks, or the green claw of the petals. Distilled waters, however carefully they may be kept, are apt to lose their aroma sooner or later; and some of them even become mouldy and acquire thereby an unpleasant odour. They have been thought to keep better with the addition of about a fortieth part of rectified spirit; which may be either put into the still with the water, or added afterwards to the distilled fluid. But the advantages of this addition, although sanctioned by the authority of the Dublin Pharmacopoeia, are doubted by practical men. And it is believed that the most effectual precaution for preserving them is to prepare them with extremely pure natural waters, such as snow, rain, or very fine spring water [Miiller], free especially of any unusual proportion of carbonic acid; and to keep them in black, orange, or red bottles, not in bottles of clear glass [Hanle]. ENEMAS. A consideration often neglected by practitioners in extempore prescriptions for administering drugs in the form of injection is, that the volume of it must vary with the object. If it be intended to evacuate the gut, the quantity of the fluid should not be less than sixteen fluidounccs or a pint. But if the medicine be intended to exert its own peculiar action through absorption, or through the nervous system, it ought to be administered in a quantity of fluid