_Treatment_ in the early stages consists in a dose of physic (aloes 6 drams) and fomentations of warm water to the sheath and penis. If there is reason to suspect the presence of infection, inject the urethra twice daily with borax 1 dram, tepid water 1 quart. When the mucopurulent discharge indicates the supervention of the second stage a more astringent injection may be used (nitrate of silver 20 grains, water 1 quart), and the same may be applied to the surface of the penis and inside the sheath. Balsam of copaiba (1 dram daily) may also be given with advantage after the purulent discharge has appeared. Every stallion suffering from urethritis should be withheld from service, as should mares with leucorrhea. STRICTURE OF THE URETHRA. This is a permanent narrowing of the urethra at a given point, the result of previous inflammation, caused by the passage or arrest of a stone, or gravel, by strong astringent injections in the early nonsecreting stage of urethritis, or by contraction of the lining membrane occurring during the healing of ulcers in neglected inflammations of that canal. The trouble is shown by the passage of urine in a fine stream, with straining, pain, and groaning, and by frequent painful erections. It must be remedied by mechanical dilatation, with catheters just large enough to pass with gentle force, to be inserted once a day, and to be used of larger size as the passage will admit them. The catheter should be kept perfectly clean and washed in a borax solution and well oiled before it is introduced. URINARY CALCULI (STONE, OR GRAVEL). These consist in some of the solids of the urine that have been precipitated from the urine in the form of crystals, which remain apart as a fine, powdery mass, or magma, or aggregate into calculi, or stones, of varying size. (See Pl. XI.) Their composition is therefore determined in different animals by the salts or other constituents found dissolved in the healthy urine, and by the additional constituents which may be thrown off in solution in the urine in disease. In this connection it is important to observe the following analysis of the horse's urine in health: Water 918.5 Urea 13.4 Uric acid and urates .1 Hippuric acid 26.4 Lactic acid and lactates 1.2 Mucus and organic matter 22.0 Sulphates (alkaline) 1.2 Phosphates (lime and soda) .2 Chlorids (sodium) 1.0 Carbonates (potash, magnesia, lime) 16.0 ----- 1000.0