8 PHARMACY 



To avoid confusion in the use of the Apothecary and Avoirdupois 

 systems, the symbols, Hi)., B, 3, and 9 should be consistently used for 

 the apothecary and the abbreviations, lb,, oz., gT., for the Avoir- 

 dupois. The abbreviation for the Troy pound is characterized by 

 the cross line dravm through the letters, lb., and should always mean 

 12 ounces, while the Avoirdupois pound stands for sixteen ounces. 

 The symbol § means an Apothecaries' ounce of 480 grains, while 

 the abbreviation oz., means an Avoirdupois ounce of 437.5 grains. 

 The grain weight is the same for both systems and therefore the ab- 

 breviation gr. will cause no confusion. The grain is, therefore, the 

 unit for both systems and the term is derived from the old system of 

 weighing, which required' that there should be used a grain of wheat, 

 well dried and from the middle of the ear (head). 



The character f3 represents 60 minims, and fB is necessary to 

 represent 480 minims. 



A minim of water weighs about one grain (0.95 gr.) but it should 

 be remembered that a minim is not the equivalent of a grain. 480 

 minims (IfS) of water weighed at the standard temperature of 25° C. 

 (77° F.) weigh 454.6 grains. The specific gravity of liquids also 

 varies so that a pint of liquid is not necessarily a pound. In writing 

 the Apothecaries' weights and measures in prescriptions, the figures 

 are written in the Roman system and placed after the symbol, as 

 gr..XX not 20 grs. In printed matter the small letters are used, 

 but in writing it is better to use the capital L, because the small 

 letter might easily be mistaken for an i. The ones should always be 

 dotted and the last one may be written like a j ; thus g iij. But 

 under no circumstances should the other be dotted, because in a hastily 

 written or blurred prescription the pharmacist often depends upon the 

 dots to differentiate an indistinct i from an 1 or a comma or period, or 

 from an imperfectly formed v. Fractions are written as common 

 fractions : gr. %o, not gr. 0.1. The f before the sign 3 or g is often 

 omitted. 



TABLE OF APPEOXIMATE OE POPULAE MEASUEES 



The popular measures are those usually found in the household. 

 They are very inexact, and should be replaced with measuring glasses 

 or some other means of measure. A common method in veterinary 

 medicine is to use homeopathic vials of certain capacities, or syringes 

 of known capacity. If spoons are used they should be filled so that 

 the fluid stands level with the rim. 



The most common of these measures are : 



1 drop (g1;t.) = 1 minim 



1 teaspoonful = 1 f 3 



1 dessertspoonful^^ 2 £3 



1 tablespoonful = 4 £3 (i/gS) 



1 wineglassful = 2 f S 



1 teacTip£til = 4 £5 



1 glassful = 8 f 5 



