30 LECTURE II. 



the other hand, it is not true, as Asher and Rosenfeld 1 have recently 

 shown, that the greater part of the glucose, or perhaps all of it, is present 

 in a combined state. Glucose from blood diffuses through a parchment 

 membrane, even when the outer liquid is a blood deficient in sugar, made 

 so by the action of yeast. Glucose is also present in certain organs (mus- 

 cles) . It is often hard to decide whether the glucose found was pre-f ormed, 

 or whether it has been produced secondarily from a carbohydrate of higher 

 molecular weight by hydrolytic fermentation. Normal human urine fre- 

 quently contains glucose, but always in very small quantities. It may 

 appear in larger amounts after a diet rich in carbohydrates, especially after 

 large amounts of grape sugar have been taken into the system. This is 

 spoken of as alimentary glucosuria. 2 



The elimination of considerable quantities of sugar in the urine has 

 been observed after the introduction of numerous chemical substances into 

 the system, as, for example, strychnin, curari, phosphorus, etc. 



The most interesting form of glycosuria is that produced by phloridzin 

 and known as phloridzin-diabetes. Phloridzin 3 is a glucoside obtained 

 from the root-bark of apple, pear, cherry, and plum trees, and yields by 

 hydrolysis glucose and phloretin: 



phloretin 



The phloretin is decomposed further into phloroglucinol and phloretic 

 acid: 



Ci 5 H 14 O 5 + H 2 = C 6 H 3 (OH) 3 + C 6 H 10 O 3 



phloroglucinol phloretic acid 



We shall consider these artificially-produced glucosurias at another 

 place. 



Glucosuria has been observed, furthermore, by Hofmeister 4 when he 

 fed starch to starved dogs. Bohm and Hoffmann 5 have described the 

 appearance of large amounts of sugar in the urine of cats which were 

 confined and protected from cooling off by coverings. Glucosuria can 

 also be produced by a cold. 



Glucose is very widely distributed in the vegetable kingdom partly as 

 such, partly in large storage deposits in the form of starch, and partly as 



1 Asher and Rosenfeld: Zentr Physiol. 19, 449 (1905). 



2 Concerning sugar in urine, see Pfliiger, Schondorf, and Wenzel; Pfliiger's Arch. 105, 

 121 (1904). It is to be remembered that chloroform, for example, when boiled in 

 alkaline solution shows a strong reducing power. 



8 J. S. Stass: Ann. 30, 192 (1840). 



4 Arch. exp. Path. Pharm. 26, 355 (1890). 



6 Ibid. 8, 271 and 375 (1878). 



