Estimation of Chlorids.--Fill the graduated tube to the 10 c.c. mark with urine; add 15 drops strong nitric acid and then silver nitrate solution (dram to the ounce) to the 15 c.c. mark. Mix by inverting several times. Let stand a few minutes for a precipitate to form, and then revolve in the centrifuge for three minutes at 1200 revolutions a minute. Each one-tenth cubic centimeter of precipitate equals 1 per cent. by bulk. The normal is about 10 per cent. This may be converted into terms of chlorin or sodium chlorid by means of the table upon page 60. Roughly speaking, the percentage of chlorin by weight is about one-twelfth the bulk-percentage. {60} TABLE FOR THE ESTIMATION OF CHLORIDS AFTER CENTRIFUGATION _Showing the bulk-percentage of silver chlorid (AgCl) and the corresponding gravimetric percentages and grains per fluidounce of sodium chlorid (NaCl) and chlorin (Cl).--(Purdy.)_ Bulk-percentage | Percentage | Gr. Per | Percentage | Gr. Per of AgCl. | NaCl. | Oz. NaCl. | Cl. | Oz. Cl. ----------------+------------+-----------+------------+-------- ¼ | 0.03 | 0.15 | 0.02 | 0.1 ½ | 0.07 | 0.31 | 0.04 | 0.19 ¾ | 0.1 | 0.47 | 0.06 | 0.28 1 | 0.13 | 0.62 | 0.08 | 0.38 1¼ | 0.16 | 0.78 | 0.1 | 0.48 1½ | 0.19 | 0.93 | 0.12 | 0.57 1¾ | 0.23 | 1.09 | 0.14 | 0.67 2 | 0.26 | 1.24 | 0.16 | 0.76 2¼ | 0.29 | 1.41 | 0.18 | 0.85 2½ | 0.32 | 1.56 | 0.2 | 0.96 2¾ | 0.36 | 1.71 | 0.22 | 1.04 3 | 0.39 | 1.87 | 0.24 | 1.13 3¼ | 0.42 | 2.02 | 0.26 | 1.23 3½ | 0.45 | 2.18 | 0.28 | 1.32 3¾ | 0.49 | 2.35 | 0.3 | 1.42 4 | 0.52 | 2.49 | 0.32 | 1.51 4¼ | 0.55 | 2.64 | 0.34 | 1.61 4½ | 0.58 | 2.8 | 0.35 | 1.7 4¾ | 0.62 | 2.96 | 0.37 | 1.8 5 | 0.65 | 3.11 | 0.39 | 1.89 5½ | 0.71 | 3.42 | 0.43 | 2.09 6 | 0.78 | 3.73 | 0.47 | 2.27 6½ | 0.84 | 4.05 | 0.51 | 2.46 7 | 0.91 | 4.35 | 0.55 | 2.62 7½ | 0.97 | 4.67 | 0.59 | 2.84 8 | 1.04 | 4.98 | 0.63 | 3.02 8½ | 1.1 | 5.29 | 0.67 | 3.22 9 | 1.17 | 5.6 | 0.71 | 3.4 9½ | 1.23 | 5.91 | 0.75 | 3.6