Doses of Medicine 429 



sized dog is approximately that for a man. Puppies 

 must not be given large doses, especially if they belong 

 to the small breeds. Colts one year old take about 

 one -third the dose of an adult horse ; at two years old, 

 about one -half the dose. The same ratio will hold with 

 regard to young cattle. 



Medicines should always be well diluted, to prevent 

 injury to the animal. In the use of medicines, two 

 sj^stems of measurement are employed. For solid sub- 

 stances apothecaries' weight is used, the following table 

 giving the weight and symbols: 



Symbol 



1 grain gr. 



20 grains = 1 scruple 9 



3 scruples = 1 dram (or drachm) 5 



8 drams = 1 ounce J 



12 ounces =1 pound . . ........ lb. 



The scruple is not often used at present in weighing 

 medicines. 



For fluid substances the following measures of 

 capacity are used : 



1 minim m. 



60 minims = 1 fluid dram f5 



8 fluid drams =1 fluid ounce f^ 



16 fluid ounces = 1 pint O. 



2 pints = 1 quart Qt. 



4 quarts =1 gallon C. 



In writing a prescription, if a fluid dram or ounce is 

 intended, the letter/ is placed before the symbol. To 

 indicate the number of measures to be taken the letter 



