The Large White Kidneys with Waxy Infiltration.--It is well known that in certain persons a peculiar morbid change takes place in the viscera. The walls of the blood-vessels and some of the glandular cells become infiltrated with a peculiar translucent substance. This morbid change is commonly known by the name of waxy or amyloid infiltration. It is known that such an infiltration occurs regularly in persons who have chronic inflammations of the bones and joints, constitutional syphilis, and pulmonary phthisis. It is also known that this new substance is colored in a special way by iodine and some of the aniline colors. Beyond this we have no real knowledge of what the substance is or how it is produced. In other parts of the body the waxy infiltration can hardly be said to produce any local symptoms. If one has a waxy liver or spleen, these organs may give the physical evidences of their enlargement, but that is all. We look upon such patients as suffering from some general changes concerning the nature of which we are ignorant, but not as suffering simply from disease of the liver or spleen. It seems at first sight natural to think of waxy kidneys in the same way--not as examples of kidney disease, but as parts of a general morbid condition. This view has been adopted by most authors. They describe the waxy kidneys as something different from the other forms of nephritis. But really this is an error. In the vast majority of cases the waxy kidneys are simply a variety of chronic diffuse nephritis. It is possible (Cohnheim) to have waxy infiltration of the Malpighian bodies without other lesion of the kidney, but this is a rare exception. The rule is that we find the ordinary lesions of chronic diffuse nephritis; and, more than this, we often find the nephritic lesions very much farther advanced than the waxy infiltration. The association of the lesions is not at all such as to give the idea that the waxy infiltration is produced first and the other lesions afterward. It is also not uncommon to find waxy infiltration of the Malpighian tufts without similar changes in any other part of the body. The type of the nephritis varies in different cases. Most of the kidneys resemble the large white kidneys, some the atrophied, some those which are neither large white nor atrophied. The clinical history varies in the same way, and is that of a large white or atrophied kidney, as the case may be. The only difference is that in some patients (not in the majority) there is a very large amount of urine passed of low specific gravity. As a matter of fact, in most cases of waxy kidneys we simply make the diagnosis of chronic diffuse nephritis, and if we add to this that of {93} waxy infiltration it is because the patients have had syphilis or bone or joint disease. Even in this way we are often enough deceived, as in the following case: