System of materia medica and pharmacy: including translations of the Edinburgh, London, and Dublin pharmacopoeias / With notes by N. Chapman.

  • Murray, J. (John), -1820
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: System of materia medica and pharmacy: including translations of the Edinburgh, London, and Dublin pharmacopoeias / With notes by N. Chapman. Source: Wellcome Collection.

    47/908 (page 33)
    This last measure is one newly introduced. In appor¬ tioning liquids into very small quantities, the quantity has been usually estimated by drops (guttse, gtt.) allowed to fall from the edge of the mouth of a bottle ; but the size of the drop is liable to vary, not only according to the mo¬ bility and specific gravity of the liquid, a circumstance of inferior importance, since with regard to each substance it remains the same, but also according to the thickness of the edge of the vessel, and the degree of inclination. The London College have therefore substituted this division of minims, which are measured in a slender graduated glass tube. It is necessary to recollect, that these minims have no strict relation to drops, as indeed is evident from the circumstance, that a drop is a very variable quantity, both in size and weight, from different liquids. A drop of wa¬ ter is equal to about a grain, but 60 grains of alcohol are equal to 175 drops of it, 60 grains of white wine to 96 drops, and 60 grains of tinctures with diluted alcohol to from 135 to 145 drops. The measures of a table and of a tea spoonful are sometimes used in extemporaneous pre¬ scription, and though not very accurate, may be admitted where a small difference in the dose is not important. The one is understood to be equal to half an ounce by measure, the other to about one drachm. I shall place here several tables, to which it may be suf¬ ficient afterwards to refer, as embodying a number of facts which it would occupy much space to detail separately, ]in College. The numbers represent Troy grains of distilled water at the temperature of 60”. Apothecary’s Measure. Imperial Measure. Grains Iroy. Gallon,. 58327.5 Pint,.7290.9 Ounce, .455.6 Drachm,... ,,.57 Grains Troy. 70000 8750 546.8 68.3 C