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MATERIA MEDICA AND THERAPEUTICS. 43 



TABLES USED IN PRESCRIPTION WRITING. 



APOTHECARIES OR TROY WEIGHT. 



20 Grains (Granum) ....(Gr. or Grs.)— I Scruple. 

 3 Scruples (Scrupulum) . . ( 9 )=i Drachm (6o Grs.) 

 8 Drachms (Drachma) . .(3)=i Ounce. 



12 Ounces (Uncia) (3)=i Pound (lb.). 



In prescription writing the pound sign should not be used; 

 always express large quantities by ounces. 



APOTHECARIES LIQUID MEASURE. 



6o Minims (Minimum) (M)=i Fluid drachm. 



8 Fluid drachms (Fluid Drachma) . . (fl. 3)=i Fluid ounce. 

 16 Fluid Ounces (Fluida Uncia) . . (fl. 3)=i Pint. 



2 Pints (Octarius) (0.)=i Quart. 



4 Quarts or 8 pints^i Gallon (congius — C.) 



In prescribing liquids the abbreviation for Quarts (Qts.) is 

 never used. 



If a quart is desired it is expressed as two pints (Oij). 



METRIC SYSTEM. 



i Milligram = 

 Fractions < Centigram = 



( Decigram = 

 Unit Gram = I 



{Decagram = io 

 Hectogram = ioo 

 Kilogram =iooo 



The line represents the decimal point. 



For liquid measure substitute the unit and suffix Liter for 



Grams. 



EQUIVALENTS. 



I Gram = 15.432 grains. 

 1 Cubic-centimeter = 16.231 minims. 

 For nearly all purposes, figuring 15 minims as equal to one 

 cubic-centimeter and 15 grains as equal to one gram is suffi- 

 ciently correct to avoid danger. 



By memorizing the prefixes and suffixes one has the entire 

 metric system at his command. 



The suffix Meter is the unit of measure of length. 

 " Gram " " " " " weight. 

 " Liter " " " " " liquids. 

 The cubic-centimeter is the cube upon one one-hundredth 

 part of a meter and is equal to one milliliter or y^nnr of a liter, 

 or about 16 minims (16.231). 



