862 JOHN R. WILLIAMS 



"a long continued abnormally increased secretion of non-saccharine urine 

 which is not caused by a diseased condition of the kidneys." 



In the succeeding years, while occasional mention is made in the 

 literature of the subject, no important contribution appeared until Claude 

 Bernard(fr) (1813-1878) published his studies on brain physiology. He 

 demonstrated that by puncture of the floor of the fourth ventricle, a 

 polyuria could be produced and he believed that he had discovered a 

 center for diabetes insipidus. Later observations showed that polyuria 

 may result from other lesions of the nervous system. 



Many workers inspired by the studies of Bernard attacked the prob- 

 lem of determining the relation to normal physiological processes of 

 various brain areas in and contiguous to the third and fourth ventricles. 

 It was shown by Magnus and Schafer in 1902 that extracts of the hy- 

 pophysis when injected into an animal caused an increased secretion of 

 urine. In 1916 Schafer and Herring demonstrated that the diuretic 

 principle of the hypophysis was in the pars intermedia. Gushing (a) and 

 his associates (1908-1912) worked extensively with the hypophysis and 

 noted among others things that after certain manipulations of the struc- 

 ture a severe polyuria followed which was sometimes of several days^ 

 duration. They directed attention to the similarity between this condi- 

 tion and diabetes insipidus. It was Cushing's conclusion that the syn- 

 drome was due to hypofunctioning of the hypophysis. 



Prevalence 



Diabetes insipidus is a very uncommon disorder or is seldom observed. 

 Fitz reports a rate of occurrence of fourteen cases per hundred thousand 

 from a statistical examination of 533,977 hospital and out-patient ad- 

 missions. The author, in a similar study which includes chiefly well 

 known American hospitals, found that 197 cases were observed in 1,935,- 

 770 hospital admissions, a rate of 19.2 per one hundred thousand. These 

 data are shown in Table No. 1, page 863. 



In many of the large general hospitals and clinics of this country, 

 no cases have been observed. It is possible that the syndrome has been 

 overlooked in some instances; on the other hand, it is probable that in 

 the absence of precise methods of study, the disorder where diagnosed 

 is sometimes confused with other diseases characterized by polyuria. Dr. 

 L. G. Rowntree of the Mayo Clinic, Rochester, Minnesota, states that 

 of a total of 257,000 admissions to the Mayo Clinic, 35 cases were in- 

 dexed as diabetes insipidus. After a careful study of the data, eleven 

 cases were discarded as being not true examples of the syndrome. Other 

 well known clinicians, including George Dock and Joseph L. Miller, have 

 expressed doubt as to the validity of the diagnosis in many cases and 



