CARBOHYDRATES 189 



this is not accompanied by increased adrenalin output it 

 must be a direct effect upon the Kver. But when the 

 muscular exertion is sufficiently intense to cause cerebral 

 anaemia increased output of adrenahn may occur, the 

 suprarenals thus playing a supplementary part in sugar 

 mobiUsation. 



Phloridzin Diabetes 



Phloridzin, a substance obtained from the roots of 

 certain trees, causes glycosuria on injection. The glyco- 

 suria, however, differs from those above described in that 

 it is not accompanied by hyperglycsemia. It is evidently 

 produced by a change in the permeabihty of the kidneys 

 to sugar. The renal origin of the condition is easily 

 proved. When the drug is injected into a renal artery 

 glucose is excreted from the corresponding kidney earlier 

 than from the opposite side. In spite of continued drainage 

 the percentage of sugar in the blood remains normal or 

 nearly normal. The need for making up in the blood the 

 amount of sugar lost through the kidneys leads to a dis- 

 turbance of carbohydrate storage and formation. The 

 importance of phloridzin diabetes therefore Hes in the hght 

 which it throws upon the capacity of the organism to 

 produce sugar. 



Human Diabetes 



The low respiratory quotient observed in diabetics shows 

 that this condition is due essentially to a loss of the power 

 of glycolysis by the tissues generally. Hyperglycsemia is 

 always present. The association of the disease with 

 degenerative changes in the pancreas was early noted, 

 and indeed was the cause of investigations into the influence 

 of that gland upon carbohydrate metabohsm. Whether 

 the pancreas is always at fault is not known. It may be 

 that pathological changes occur not visible on post-mortem 

 examination. As to the location of the cause of the 

 disease in the Islets of Langerhans, it has been found that 



