Gall-stone disease may be regarded as of great importance in estimating an individual’s prospects of longevity, and at the same time as a pathological manifestation of an inactive thyroid, or deficient sexual glands in women. This applies equally well to the cause of renal colic, gravel, which was found by Professor Sajous to be prevented by thyroid preparations and a suitable diet. Constipation, an important predisposing cause, has been shown to be an expression of such conditions. The truth of these assertions is proved by experimental evidence. Extirpation of the thyroid provokes important changes in the liver. In myxœdema there is a condition of hepatic cirrhosis, as shown by Prun-Hudden, Vermehren,[138] and others. Two years after we had shown that the thyroid and liver stand in close relation to one another, Professor Neusser, of Vienna, brought forward the same conclusion at the German Congress of Internal Medicine in 1906. Footnote 138: Over Myxœdemet, Kjöbenhavn, 1895. Another important gland that has a very close connection with the thyroid is the kidney. A direct examination of this organ is not possible, but we have means of readily judging of its efficiency by observing how it performs its function. This is to eliminate waste and poisonous products from the body by means of its secretion—the urine. Thus from the examination of the urine we may gather all the information necessary about the activity of the kidneys. In examining the urine we must first pay attention to its appearance, the daily amount, and its specific gravity. Less than about two pints a day of a light colored urine, with a specific gravity below 1020, indicates a faulty action of the kidneys, and the possibility of a large amount of toxic products being retained, instead of being eliminated. Such a urine can often be seen in cases of thyroid insufficiency, as this condition of the thyroid causes a diminution in the activity of the kidneys. As we have shown in a communication to the Paris Biological Society,[139] the thyroid and the kidneys are very closely related, changes in the thyroid always being followed by changes in the kidneys. Thus it was found by Albertoni and Tizzoni, by Blum and others, that extirpation of the thyroid is followed by fibrosis of the kidneys. Interstitial nephritis is the rule in myxœdema, and is very frequent in all conditions with insufficiency of the thyroid. In such patients the quantity of urine is diminished, and also its specific gravity, as well as the quantity of urea and uric acid, which in consequence are retained in the body. Footnote 139: Loc. cit.