SOLUTIONS.
Reading edition
TO MAKE A 1: 500 SOLUTION.
Add 1 gr. or 1 m. to 1 ounce of water
Add 15 “ 15 “ 1 pint “
Add 30 “ 30 “ 1 quart “
Add 120 “ 120 “ 1 gallon “
To make 1 : 1000 sol. take 1 part of 1.500 sol. and 1 part water.
To make 1 : 2000 “ 1 part of 1.500 “ 3 parts water.
To make 1 : 4000 “ 1 part of 1.500 “ 7 “
To make 1 : 5000 “ 1 part of 1.500 “ 9 “
To make a 1: 500 solution of formaldehyd add 38 minims of formalin (a 40 per cent. solution of formaldehyd) to 1 pint of water.
A HANDY SOLUTION TABLE WITH DOMESTIC MEASURES.
SOLUTION. DOMESTIC MEASURE.
1 : 1000 1 teaspoon to gallon.
⅒ of 1 per cent. 15 drops to quart.
1 : 500 2 teaspoons to gallon.
⅕ of 1 per cent. 30 drops to quart.
1 : 200 5 teaspoons to gallon.
½ of 1 per cent. 1¼ teaspoons to quart.
1 : 100 2½ teaspoons to quart.
1 per cent. 1¼ teaspoons to pint.
1 : 50 5 teaspoons to quart.
2 per cent. 2½ teaspoons to pint.
1 : 25 2½ tablespoons to quart.
4 per cent. 5 teaspoons to pint.
1 : 20 3 tablespoons to quart.
5 per cent. 1½ tablespoons to pint.
TO PREPARE A 1: 500 SOLUTION.
There are 7680 m. in 1 pint of solution (water); therefore we divide 7680 by 500 as follows:
500)7680(15⅗ m. to 1 pint of solution (water).
500
2680
2500
1800
1500
300, or ⅗ of a m.
N.B.—Divide the number of m. in 1 pint by the strength of the solution, and then divide the result by the percentage of original strength of the article.
When original strength of solution is less than 100 per cent., as, for example, formaldehyd, which is 40 per cent., divide the quotient above resulting by the percentage of strength—viz.:
40)1536(38⅖ m. to 1 pint of solution (water).
120
336
320
¹⁶/₄₀ = ⅖.
To get a ¹/₁₀₀ of a grain dose of any drug out of a solution of 60 minims containing ¹/₃₂ of a grain of that drug, compute as follows:
³²/₃₂ or 1 grain = 32 × 60, or 1920 m.
¹/₁₀₀ = ¹/₁₀₀ of 1920 m.
100)1920(19⅕ m.
100
920
900
20, or ⅕ m.
Rule.—Multiply the quantity of the solution on hand in minims by a number indicating the fractional amount of the drug therein contained, and divide by a number indicating the fractional amount of the drug desired.
In 20 parts of solution we have 1 part of carbolic acid.
In 1 part “ “ ¹/₂₀ “ “
In 100 parts “ “ 100 × ¹/₂₀ = 5 pt. “
40 parts contain 1 part of carbolic acid.
1 part contains ¹/₄₀ “ “
So that ¹/₄₀ solution is a 2½ per cent. carbolic acid solution.