536 DIABETES 



11 Bronzed Diabetes," In this condition there appears a wide-spread 

 deposition of an iron-containing pigment in the tissues and organs of 

 the body, associated with the accumulation of an iron-free pigment in 

 places where normally pigment is found in smaller amounts. This sub- 

 ject is discussed under "Pigmentation" (page 404). The diabetes is 

 due to an interstitial pancreatitis, and must be considered as secondary to 

 the disease, hemochromatosis, and not primary. 1 The cause of the dis- 

 ease is unknown. 



CHRONIC POLYURIA 



" Diabetes insipidus,'' which in some instances terminates in diabetes 

 mellitus, but most generally seems to be quite distinct from true diabetes, 

 presents little for consideration from the chemical side. Most striking, 

 but by no means constant or characteristic, is the occurrence of inosite 

 in the urine, sometimes in considerable quantities. Inosite, which 

 occurs normally in the muscles, liver, spleen, kidneys, and other organs,' 2 

 has been frequently found in the urine in both normal and pathological 

 conditions. Although its empirical formula, C 6 H 12 O 6 , is identical with 

 that of the hexoses, yet it is a benzene derivative (Maquenne), having 

 the following formula : 



X CHOH CHOHL 



CHOH( )CHOH. 



X CHOH CHOH/ 



The normal constituents of the urine are generally increased in total 

 amount, as if washed out with the excessive elimination of water. Con- 

 sequently patients with this disease suffer from thirst and hunger, and 

 drink and eat abnormally great quantities. Meyer 3 states that the con- 

 centration of the urine tends to remain uniform, and that the amount of 

 water is varied to regulate the concentration according to the amount of 

 solids that are eliminated. 



The etiology of the disease is unknown, but is probably various. 

 Often it seems to be hereditary, but sometimes has been found associated 

 with lesions in the pons, medulla, or cerebellum, which agrees with the 

 observation of Bernard that experimental injuries of these parts may be 

 followed by polyuria without glycosuria. In any case the increased flow 

 of urine seems to be due to a dilatation of the vessels of the kidney, 

 without increased arterial pressure ; 4 indeed, abnormally low blood pres- 

 sure is often present. Presumably this vasodilatation depends upon 

 nervous influences ; a similar condition may be produced in animals by 

 cutting the renal nerves. 5 



1 See Opie, Jour. Exper. Med., 1899 (4), 279; Anschiitz, Dent. Arch, klin, 

 Med., 1899 (62), 411 ; Hess and Zurhelle, Zeit. klin. Med., 1905 (57), 344. 



2 See Meillere, " Inosurie. Recherche de 1' inosite dans les tissus, les secre- 

 tions et les excretions." Paris, 1906. 



3 Dent. Arch. klin. Med., 1905 (83), 1. 



4 Review and literature by R. Schmidt, Wien. klin. Woch., 1905 (18), 1112. 



5 Tallqvist (Zeit. klin. Med., 1903 (49), 181) on the basis of a study of the 

 conditions of metabolism, suggests that the polyuria of diabetes insipidus may 

 be due to a defective resorption of water in the renal tubules. 



