636 DIABETES 



alios of the fat metabolism tlie reader is referred to the section on 

 aeidosis. 



Whereas the normal urine at all times contains reducing sub- 

 stances and substances Avliich are optically active, which yield crys- 

 talline compounds with the hydrazines and respond to other so-called 

 sugar tests, these substances are not all sugars, nor are all the sugars 

 glucose. The quantity of fermentable reducing substance in normal 

 urine averages about 4 parts in 10,000 (0.04 per cent.) (Lavesson).- 

 This is doubtless subject to change depending upon the diet and 

 many other physiologic factors. The total reducing substance in the 

 normal urine of adults averages 0.21 to 0.24 per cent., of which glucose 

 constitutes but 18 per cent. (Bang and Bohmannson).^ When an 

 abnormal amount of sugar occurs in the urine regardless of the kind, 

 the condition may be called, in accordance with Naunyn's suggestion, 

 melituria (or glycurui). When the sugar is glucose (dextrose), the 

 term glycosuria is applied; when levulose, Icvulosuria, etc. Other 

 known forms of melituria are lactosuria, galactosuria, fructosuria, 

 pentosuria, etc. All these are but symptoms, many of them being 

 caused by a variety of mechanisms, which will be discussed presently. 



The term diabetes is often loosely used to cover any variety of 

 inelituria, but it is preferably limited to certain forms ; namely, to 

 the glycosurias (or the mixed meliturias in which d-glucose is the 

 predominating sugar), and further than this, to those particular 

 glycosurias which continue even after the glycogen reserves of the 

 body have become depleted and when the diet is free of carbohy- 

 drate ; or, to those transient glycosurias whose nature by one means or 

 another can be proven to be identical with the continuous forms (la- 

 tent or mild diabetes). Over against these are the meliturias in which 

 other sugars than glucose play the chief role, and glycosurias which 

 are essentially transient because they depend solely on the ingestion 

 or administration of excessive quantities of glucose or the sudden 

 liberation into the blood of glucose derived from preformed glycogen 

 or other fixed compound of sugar. 



Thus, the gh-cosuria which follows puncture of the floor of the 

 fourth ventricle (Claude Bernard's piqilre) does not occur in animals 

 which contain little glycogen. The same apj^lies to the adrenal, thy- 

 roid and hy])()pliysis glycosurias. But after comi)lete pancreas ex- 

 tirpation (pancreas diabetes) and in the spontaneous human disease 

 (diabetes melitus) or its coujiterpai't in animals, and during the con- 

 tinuous administration of ])lil()iliiziii, the glycogen may be nearly or 

 (|uite exhausted and the diet consist solely of meat and fat and still 

 the glycosui'ia continue. On the other hand a partial ])ancreas extir- 

 pation, a mild diabetes melitus, oi- an interrupted phlorhizinization 

 may give rise to transient glycosui-ia, the diagnosis of which may be 



zBioclii'iii. /('it., 1007 (4), 40. 



3 Zoit. pliysiol. Chem., 1!)0;», (03), 443. 



