DISTURBANCES OF CARBOHYDRATE METABOLISM 293 



bini, Alexander and others in which the diagnosis is not thoroughly 

 established. 



The disorder is not common. Salkowski(d) (1899) tried for six or 

 seven years to discover new cases, but succeeded in finding only two in 

 addition to the one he first described. These were reported by Blumen- 

 thal(a). Adler(6), working at Carlsbad, examined 7,726 urines, of 

 which 1,490 reduced alkaline copper solutions. Of these, only two were 

 pentose urines. A more frequent occurrence is indicated by the results 

 of Jolles(a)(1905), who reported having found four pentose urines in 

 3,000, examined in the course of two years. A still greater proportion of 

 pentose urines is claimed by Stookey. In two years he had one hundred 

 urines that gave a slight reduction with Fehling's solution. Of these, fif- 

 teen gave pentose reactions. He believes he excluded all alimentary pento- 

 suria. The total number of urines examined is not given but, if Stookey's 

 results are correct, pentosuria cannot be quite so unusual as is generally 

 believed. 



Causation. The etiology is unknown. In one case (Rosenfeld), the 

 urine is definitely stated to have been regularly free from reducing sub- 

 stances up to not more than one and three-quarter years before a railway 

 accident, in which the patient suffered trauma and shock, and after 

 which the pentosuria was observed. The disorder has been observed at 

 as early an age as five years (Aron(fr)). The condition is approximately 

 three times as frequent among men as among women. 



A congenital factor is almost certainly involved in some cases. In 

 only twenty-one cases is the family history reported, but of these nine 

 come from four families. In addition to these, there are nine others in 

 which diabetes is said to have existed in the family. It is quite likely 

 that some of these "diabetes" were, in reality, pentosurias. A real connec- 

 tion with diabetes may exist, but a definite conclusion is unwarranted in 

 view of the uncertainty as to the diagnosis of diabetes in many cases. 

 The relatively frequent occurrence of pentosuria among Jews (seven 

 patients in six families are definitely stated to have been Jews) may 

 help to account for the frequent occurrence of diabetes in the family 

 history. Moreover, a member of a diabetic family is more likely to wish 

 to have his urine examined frequently than is the member of a non-diabetic 

 family, and an existing pentosuria is therefore the more likely to be 

 detected. The frequent occurrence of neurasthenia, or of a neurotic con- 

 dition in the patient or his family may, similarly, be connected with the 

 large number of Jewish patients, or with the effect upon the patient of the 

 diagnosis of a persistent diabetes. Moreover, an innocuous condition such 

 as pentosuria is more likely to come to the attention of the physician when 

 occurring in a neurotic individual. 



Diagnosis. The condition appears to be unrecognized by the patient 

 until the urine is examined because of some other illness or in the course 



