It is advisable to drink plenty of water, especially when much meat, or the above-mentioned sauces, are eaten. By this means we can flush out of our kidneys the end-products of proteid food, and also other toxic substances. For the same reason it is well to use certain mineral waters with diuretic properties. They should, however, not be taken at the same moment as substances irritating to the kidneys are taken, or the kidneys may be so injured that acute hæmorrhagic nephritis may ensue. We[231] have published such a case, where even small quantities of chloride of potassium taken on an empty stomach, together with Wildungen waters, which have very diuretic properties, provoked a condition of acute nephritis, with great quantities of blood clots, epithelial and granular casts, many epithelial cells, and red and white blood-corpuscles in the urine. Footnote 231: Journal méd. de Bruxelles, 1903. When taking various drugs, we must always remember that they must pass through our kidneys. The drug habit, especially when irritating drugs are taken, can have a ruinous effect on these vital organs and surely diminish our prospects for a long life. Day by day many of the epithelial cells will be desquamated, slowly but surely, and inflammatory conditions of the kidneys will eventually appear. There is nothing in this world without a cause, and if a chronic parenchymatous or interstitial nephritis suddenly appear, it must have a pre-existing cause. It is the result of our continual neglect and abuse of these most important organs. As Prof. Friedlich Müller said a few years ago, the kidneys never forget the wrong they once have suffered. Indeed, most of the evil that befalls us in this world is our own fault, for doing things we should not do and omitting those we should. A frequent source of renal diseases is infectious diseases with the passage of toxic products through the kidneys. This source of kidney disease is often overlooked, the symptoms of acute nephritis being mistaken for or confused with those of the infectious disease. Acute nephritis after tonsillitis is often not diagnosed unless the symptoms are very marked. In such cases occasional casts and epithelial cells, with red and white blood-corpuscles, may remain for a long time in the urine, sometimes permanently, and thus slowly and insidiously chronic nephritis develops. Tonsillitis is often caused by the dropping upon the tonsils of mucous secretion from a post-nasal catarrh. This is commonly so in chronic rhinitis caused by adenoid vegetations. The best prevention of renal diseases in these cases is operation on the vegetations and treatment of the rhinitis, rather than removal of the tonsils, which probably play a great rôle in the defense of the organism against infections. This is shown by the fact that they are inflamed in the early stages of many infectious diseases.