will is perhaps the least objectionable of such agents, but potassium or sodium acetate or citrate, or even sodium chloride, in weak solution, may be given. In some cases benefit will come from a moderate use of the balsam of copiaba, or the leaves of buchu, which may improve the tone of the secretory elements. The most promptly effective of these agents is pilocarpin (Friedberger and Fröhner), but it has the serious drawback of inducing profuse and dangerous depletion and debility. Yet in careful hands, and with good cardiac tone, it may often be used to advantage. Fomentations over the loins, warm baths and mustard embrocations, may at times be beneficial. Attempts have been made to check the hyperplasia by the use of arsenic, mercury or the compounds of iodine, but their use in such cases is based on theory rather than accomplished results. HYPERTROPHY OF THE KIDNEY. Hypertrophy of both kidneys has not been recorded in domestic animals. On the other hand the extraordinary development of one in compensation for the loss or atrophy of the other is not uncommon. In this the organ follows the general law of adaptation, seen in the double symmetrical organs (testicle, etc.) and the more so that its functional activity is indispensable to life. Among _causes_ are: blocking of an ureter by calculus, worms, neoplasm, nephritic abscess, gangrene, etc. The enlargement of the remaining kidney is a vicarious act and essentially a physiological one. If compensation is perfect, it may be impossible to detect symptoms apart from those of the primary disease. _Prognosis._ Life is endangered in case of any subsequent kidney disease. ATROPHY OF THE KIDNEY. Result of hyperplasia of connective tissues and compression and absorption of parenchyma. Unilateral or partial. Causes: chronic productive inflammation, calculus in tubes, ureter, or pelvis, tumor, retention cyst, embolism. Lesions: sclerosis of kidney, firmness, pallor, anæmia, lack of glomeruli and tubules, cysts, congenital, urinous retention, colloid. Symptoms: reduced secretion, palpation of kidney. Treatment: Prevention: arrest conditions, abundance of water, succulent food, parasiticides, operation on cysts, counteract nephritis.