Metric Equivalent.

1 grain abbreviated gr.................................64.7987 mgms.

437.5 grs.- 1 ounce.abbreviated Oz. or ...............28.349 gms.

7,000 grs. 16 oz. 1 pound, abbreviated lb..............453.59 gms.

Very commonly a weight known as a drachm (dr. or ) equivalent to 60 grains (3.8879 gms.) is employed in prescribing and dispensing and more rarely the scruple Є equivalent to 20 grains. Both these weights are survivals of the Troy system and it is the common practice of pharmacists in spite of the ruling of the Pharmacopoeia to use in dispensing the Troy ounce of 480 grains, unless there is some indication that the Imperial ounce is intended. (If the signbe used it is customary to dispense 480 grains, while if the word ounce be written the Imperial ounce would be dispensed).