The Elements of Bacteriological Technique Part 128

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 pota.s.sium 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 _t.i.tre_ 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.