92 PBE8CBIPTI0N WBITING 



usually expressed in ordinary Arabic characters, except ^, 

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

 semis, the Latin for one-half. 



APPROXIMATE EQUIVALENTS OP WINE UNITS IN DOMESTIC 

 MEASUBES. 



There are usually about six teaspoonfuls 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 Oc. The 4 ounce bottle is the 

 common size, employed in canine practice, containing 24 

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

 are more appropriate for larger animals. 



THE METRIC SYSTEM. 



The metric system will be described, because it is the 

 universal system employed in scientific writings, and is now 

 official. It is based on the fact that a uniform, unchange- 

 able standard is employed as the unit of all measures, 

 whether of weight, capacity or area. This standard is the 

 ten-millionth part of the distance from either pole to the 

 equator, and is denominated a meter (39.371 inches), and is 

 the standard of length. The cube of 0.1 of a meter is taken 

 as the unit of capacity and called a litre (2.1135 pints). The 

 weight of water at its greatest density, 4° C. (39.2° F.), 

 which this cube will contain, is termed a kilogram (2.2046 

 lbs. Avoirdupois), and is the unit of the measure of weight. 



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