90 PRESCRIPTION WRITING 



usually expressed in ordinary Arabic characters, except J, 

 which is often indicated by a double s (ss), standing for 

 semis, the Latin for one-half. 



APPROXIMATE EQUIVALENTS OP WINE UNITS IN DOMESTIC 

 MEASURES. 



Teaspoon = 3 i.-ii. = 5 Cc. 



Desert spoon = 3 ii. = 10 Cc. 



Table spoon = § ss. = 15 Cc. 



Cup = 3 iv. = 120 Cc. 



Tumbler = § viii. = 260 Cc. 



There are usually about six teaspooufuls to the fluid 

 ounce. It is a good plan to have some regard for the size 

 of vials generally kept by druggists, and to write for a 

 quantity to fill the bottle. The bottles commonly in use in 

 human and canine practice are the 2 and 4 drachm ; the 1, 

 2, 3, 4, 5, 6, 8, 12, and 16 ounce. 



The 2 drachm bottles are useful for measuring the dose 

 of fluid extracts for horses ; the 3 ounce bottle is convenient 

 in writing prescriptions in the metric system for dogs, as it 

 holds approximately 100 Cc. The 4 ounce bottle is the 

 common size, employed in canine practice, containing 24 

 doses of one teaspoonful each. The J pt. and pt. bottles 

 are more appropriate for larger animals. The metric system 

 will be described, because it is the universal system em- 

 ployed in scientific writings, and is noW official. It has the 

 advantage of being arranged decimally, which makes the 

 computation of percentages easy, and the transference of a 

 quantity of one denomination to that of another, by merely 

 shifting a decimal point. The system has another value, at 

 least theoretically, in having one unit for weights and 

 measures. The unit of the fluid measure is 1 cubic centi- 

 meter of water, which at 4P Cent, weighs 1 gram. As a 

 matter of fact, fluids are dispensed in the metric system by 

 measuring them in Cc, and if liquids were all of the same 

 density as water, they would be equivalent to grams of 

 water when measured in Cc. Unfortunately this is not the 

 case. Theoretically, medicine should be dispensed by 



