Less obvious, though no less important, is the partial protection that can be afforded to weakened or disabled kidneys by judgment and discrimination in the matter of diet. In acute or chronic nephritis, forms of so-called Bright’s disease, is there not danger of overtaxing organs already weakened by placing upon them the daily duty of excreting large amounts of solid nitrogenous waste, as well as of the various inorganic salts which are so intimately associated with many of the organic foodstuffs? The consumption of excessive and unnecessary amounts of proteid food simply means the ultimate formation of just so much more urea, uric acid, etc., which must be passed out through the kidneys. In the words of Bunge, “There is no organ in our body so mercilessly ill treated as the kidneys. The stomach reacts against overloading. The kidneys are obliged to let everything pass through them, and the harm done to them is not felt till it is too late to avoid the evil consequences.” It would seem the part of wisdom, therefore, to adjust the daily intake of proteid food to as low a level as is consistent with the true needs of the body, in those cases where the kidneys are at all enfeebled, or where it seems desirable to exercise due precaution as a possible means of prevention. Equal care is frequently called for in connection with the mineral matters which enter so largely into many natural foodstuffs, or which are introduced as condiments. As an illustration, we may note one or two peculiarities in the distribution of sodium and potassium salts in the tissues of the body. Potassium is an indispensable constituent of every living cell, and the latter has the power of absorbing and holding on to such amounts of this particular element as may be necessary for the functional activity of the tissue of which it is a part. Sodium, on the other hand, stands in a different relationship to living structures. It is widely distributed, but in the higher animals, as in man, sodium salts are most abundant in the fluids of the body, notably in the plasma of the blood. Herbivorous animals have a strong liking for sodium chloride or common salt, but this is not true of carnivorous animals; indeed, the latter animals have a great dislike for salty articles of food. Vegetable products are all rich in potassium salts, whereas ordinary animal foods, such as meat, eggs, milk, and blood, are relatively poor in this element.