668 DIABETES 



Levene collected the bile of phlorhizinized dogs and found that it 

 exhibited reducing power after the phlorhizin injection, but not 

 before. Ray, McDermott and Lusk failed to find similar properties 

 in vomited bile from phlorhizinized dogs. Brauer repeated Levene's 

 work — -using a different method in that he cleared the bile with lead 

 acetate prior to making the sugar tests, and then found no reducing 

 substance. Woodyatt obtained results like Levene's but found later 

 no reaction for sugar when the bile was cleared in the way Brauer 

 recommended. Still, in the native state it yields characteristic crj^s- 

 tals of an osazon, and ferments with yeast after, but not before 

 phlorhizinization. Karl Grube perfused tortoise livers with salt 

 solution containing phlorhizin and was able to cause more rapid 

 deglycogenation than when the same salt solution minus phlorhizin 

 was used in control experiments. Now Ray, McDermott and Lusk, 

 in working with bile which had been in the alimentary tract, used 

 material that had had time to lose its sugar by resorption. Brauer's 

 clearing method may take out a trace of sugar even if present origi- 

 nally, and it must be said that there is some evidence favoring the 

 idea that phlorhizin acts in the liver, although much less strongly 

 than in the kidneys. Attempts have also been made to demonstrate 

 a direct action of phlorhizin on the mammary (Cornevins) and sweat 

 glands (Delmare). Cornevins' positive findings were not confirmed 

 by Cremer and Porcher, whereas Delmare 's work has not been re- 

 peated. But R. Pearce, working with a blood-sugar method, found an 

 increase of sugar in the pancreatic juice, and Underbill has brought 

 further evidence in support of a general action. M. H. Fischer had 

 some nephrectomized frogs, which are able to live indefinitely in water 

 because they excrete through the skin. With the writer some of 

 these frogs were injected with phlorhizin into the dorsal lymph sac, 

 and sugar was found next day in the water in which the frogs were, 

 but not in the water Occupied by control frogs. The possible origin 

 of this sugar in the slime makes it desirable to repeat this crucial ex- 

 periment. Although the view most commonly held is that phlorhizin 

 acts specifically and exclusively on the kidney cells this has never 

 been proved, and there is much to suggest a general cell effect ex- 

 hibited most strikingly in the kidney. • 



Regarding the fundamental nature of the action of phlorhizin, 

 nothing satisfactory has been evolved. Minkowski suggested that 

 phloretin and sugar are split apart in the kidne.y epithelium, and that 

 the sugar is then excreted while the phloretin is retained in the body. 

 The retained phloretin then takes up a new molecule of glucose from 

 the blood to reform phlorhizin, — which in the kidney is again split, 

 etc. (vehicle theory). Zuntz has determined with a given minute dose 

 of phlorhizin how much sugar can be eliminated in a given time by one 

 kidney; then, figuring what weight of phlorhizin is in the kidney, and 

 how much sugar comes out of the kidney, he reckons how frequently 



