FACTORS FOR CONVERTING FROM ONE SYSTEM TO THE OTHER.
To convert grammes into grains 15.432.
To convert grammes into ounces avoirdupois 0.03527.
To convert kilogrammes into pounds 2.2046.
To convert cubic centimetres into fluid ounces imperial 0.0352.
To convert litres into fluid ounces imperial 35.2.
To convert metres into inches 39.37.
To convert grains into grammes 0.0648.
To convert avoirdupois ounces into grammes 28.35.
To convert troy ounces into grammes 31.104.
To convert fluid ounces into cubic centimetres 28.42.
To convert pints into litres 0.568.
To convert inches into metres 0.0254.
TABLE FOR THE CONVERSION OF DEGREES CENTIGRADE INTO DEGREES FAHRENHEIT.
_X. C. = ((9x/5) + 32) F._
Cent. Faht. Cent. Faht. Cent. Faht. 0 32.0 34 93.2 68 154.4 1 33.8 35 95.0 69 156.2 2 35.6 36 96.8 70 158.0 3 37.4 37 98.6 71 159.8 4 39.2 38 100.4 72 161.6 5 41.0 39 102.2 73 163.4 6 42.8 40 104.0 74 165.2 7 44.6 41 105.8 75 167.0 8 46.4 42 107.6 76 168.8 9 48.2 43 109.4 77 170.6 10 50.0 44 111.2 78 172.4 11 51.8 45 113.0 79 174.2 12 53.6 46 114.8 80 176.0 13 55.4 47 116.6 81 177.8 14 57.2 48 118.4 82 179.6 15 59.0 49 120.2 83 181.4 16 60.8 50 122.0 84 183.2 17 62.6 51 123.8 85 185.0 18 64.4 52 125.6 86 186.8 19 66.2 53 127.4 87 188.6 20 68.0 54 129.2 88 190.4 21 69.8 55 131.0 89 192.2 22 71.6 56 132.8 90 194.0 23 73.4 57 134.6 91 195.8 24 75.2 58 136.4 92 197.6 25 77.0 59 138.2 93 199.4 26 78.8 60 140.0 94 201.2 27 80.6 61 141.8 95 203.0 28 82.4 62 143.6 96 204.8 29 84.2 63 145.4 97 206.6 30 86.0 64 147.2 98 208.4 31 87.8 65 149.0 99 210.2 32 89.6 66 150.8 100 212.0 33 91.4 67 152.6
TABLE FOR THE CONVERSION OF DEGREES FAHRENHEIT INTO DEGREES CENTIGRADE.
_X F. = (5(x - 32))/9 C._
Faht. Cent. Faht. Cent. Faht. Cent. Faht. Cent. Faht. Cent.
32 0. 68 20.0 104 40.0 140 60.0 176 80.0 33 0.6 69 20.6 105 40.6 141 60.6 177 80.6 34 1.1 70 21.1 106 41.1 142 61.1 178 81.1 35 1.7 71 21.7 107 41.7 143 61.7 179 81.7 36 2.2 72 22.2 108 42.2 144 62.2 180 82.2 37 2.8 73 22.8 109 42.8 145 62.8 181 82.8 38 3.3 74 23.3 110 43.3 146 63.3 182 83.3 39 3.9 75 23.9 111 43.9 147 63.9 183 83.9 40 4.4 76 24.4 112 44.4 148 64.4 184 84.4 41 5.0 77 25.0 113 45.0 149 65.0 185 85.0 42 5.6 78 25.6 114 45.6 150 65.6 186 85.6 43 6.1 79 26.1 115 46.1 151 66.1 187 86.1 44 6.7 80 26.7 116 46.7 152 66.7 188 86.7 45 7.2 81 27.2 117 47.2 153 67.2 189 87.2 46 7.8 82 27.8 118 47.8 154 67.8 190 87.8 47 8.3 83 28.3 119 48.3 155 68.3 191 88.3 48 8.9 84 28.9 120 48.9 156 68.9 192 88.9 49 9.4 85 29.4 121 49.4 157 69.4 193 89.4 50 10.0 86 30.0 122 50.0 158 70.0 194 90.0 51 10.6 87 30.6 123 50.6 159 70.6 195 90.6 52 11.1 88 31.1 124 51.1 160 71.1 196 91.1 53 11.7 89 31.7 125 51.7 161 71.7 197 91.7 54 12.2 90 32.2 126 52.2 162 72.2 198 92.2 55 12.8 91 32.8 127 52.8 163 72.8 199 92.8 56 13.3 92 33.3 128 53.3 164 73.3 200 93.3 57 13.9 93 33.9 129 53.9 165 73.9 201 93.9 58 14.4 94 34.4 130 54.4 166 74.4 202 94.4 59 15.0 95 35.0 131 55.0 167 75.0 203 95.0 60 15.6 96 35.6 132 55.6 168 75.6 204 95.6 61 16.1 97 36.1 133 56.1 169 76.1 205 96.1 62 16.7 98 36.7 134 56.7 170 76.7 206 96.7 63 17.2 99 37.2 135 57.2 171 77.2 207 97.2 64 17.8 100 37.8 136 57.8 172 77.8 208 97.8 65 18.3 101 38.3 137 58.3 173 78.3 209 98.3 66 18.9 102 38.9 138 58.9 174 78.9 210 98.9 67 19.4 103 39.4 139 59.4 175 79.4 211 99.4 212 100.0
~Percentage Formula~ for addition of salts, etc., to completed media.
~Formula for preparing any desired percentage~ of a given salt, etc., in tubed media; e. g., to make 4 per cent. solution of KNO_{3} in a series of tubes of broth each containing 10 c.c. of medium, when there is already available a 25 per cent. stock aqueous solution of potassium nitrate.
(_N_ + ~X~) _Y_ _A_ (~X~) --------------- = ---------- 100 100
_N_ = number of cubic centimetres contained in each tube.
~X~ = amount of stock solution to be added to each tube.
_Y_ = percentage required in the medium.
_A_ = percentage of stock solution.
Then
(10 + ~X~) 4 25 ~X~ ------------ = ------ 100 100
Therefore, 40 + 4~X~ = 25~X~.
Therefore, 21~X~ = 40.
~X~ = 1.9 c.c.
This allows for solution added to the original bulk of medium.
Therefore, 10 c.c. broth + 1.9 c.c. of a 25 per cent. aqueous solution KNO_{3} makes 11.9 c.c. medium containing 4 per cent. KNO_{3}.
~TABLES FOR PREPARING DILUTIONS~
(of Serum, Disinfectants or other substances.)
In estimating the agglutinin content or _titre_ of a serum, testing disinfectants and for many other purposes, it becomes necessary to prepare a series of dilutions of the material under examination, and in order to avoid unnecessary expenditure of labour it is convenient to adhere to some definite scale of increment, such for example as the following:
From dilutions of 1:10 to 1:80 rise by increments of 5.
From dilutions of 1:80 to 1:200 rise by increments of 10.
From dilutions of 1:200 to 1:400 rise by increments of 25.
From dilutions of 1:400 to 1:500 rise by increments of 50.
From dilutions of 1:500 to 1:1000 rise by increments of 100.
From dilutions of 1: 1000 to 1:5000 rise by increments of 250.
From dilutions of 1: 5000 to 1:10,000 rise by increments of 1000.
From dilutions of 1:10,000 to 1:100,000 rise by increments of 5000.
From dilutions of 1:100,000 to 1:1,000,000 rise by increments of 100,000.
When dealing with a substance of unknown powers--and this is especially true with regard to agglutinating sera--it is customary to run a preliminary test, using a few widely separated dilutions such as may be obtained in the following manner:
FIRST DILUTION--I.
1 c.c. serum + 9 c.c. normal saline solution = 10 per cent. solution or 1: 10 dilution (of which 1 c.c. contains 0.1 c.c. of the original serum).
When dealing with fluids other than serum the diluent is usually distilled water; whilst if the original substance is a solid the instructions would read:
1 gram o.s. + 10 c.c. distilled water = 10 per cent. solution, etc.
SECOND DILUTION--II.
1 c.c. first dilution + 9 c.c. normal saline solution = 1 per cent.