122 PHYSIOLOGY. 



blood before it can serve any needs in the economy. From our data 

 we are led to believe that the glycogen is formed and stored up 

 in the liver-cell protoplasm, and the appearance of sugar is due to its 

 transformation by liver diastase, to be absorbed into the hepatic veins. 

 Glycogen is formed most abundantly from carbohydrate food and 

 from fats (Pfliiger), and next from proteids. On a diet rich in 

 carbohydrates, the glycogen of the liver reaches 15 per cent., while in 

 a state of starvation it may.be so small as to escape the tests. 



Uses. 



The liver is the chief storehouse of the carbohydrate material. 

 Thus the use of the glycogenic function of the liver is supposed to be 

 that of continuously supplying material which may be easily oxidized 

 for the purpose of maintaining animal heat and motion. Sugar is a 

 very unstable article in the presence of oxygen with albuminoid sub- 

 stances. The sugar becomes oxidized, both in the blood during 

 respiration as well as in the tissues supplied by the blood. 



DIABETES. 



Diabetes is a chronic affection characterized by the constant pres- 

 ence of grape-sugar in the urine, an excessive urinary discharge, and 

 progressive loss of flesh and strength. Its exact pathology is as yet 

 unknown, but seems to be intimately associated with certain nervous 

 affections, disturbed hepatic and pancreatic functions, sexual excesses, 

 while heredity also seems to play an important role. 



Simple Glycosuria must be differentiated from the disease dia- 

 betes (mellitus), since the former is but a temporary condition, and 

 not a disease. When excessive quantities of sugar, maltose, etc., are 

 eaten by a perfectly healthy individual, sugar appears in the urine, 

 due to the fact that all of the absorbed sugar cannot be carried into 

 the portal circulation fast enough, so that some finds its way into the 

 thoracic duct and by it is emptied at once into the general circulation. 

 Before reaching the liver, where it would be stored up as glycogen, it 

 passes through the kidneys, there to be promptly eliminated. This 

 temporary condition has been termed simple, or alimentary, glyco- 

 suria. Dietary conditions, in the way of abstaining from starchy and 

 saccharine foods, will promptly eradicate this condition. Simple 

 glycosuria may also result from the inhalation of chloroform, tur- 

 pentine, use of chloral, etc. ; it may be one of the conditions following 

 injury to the head. Diabetic glycosuria differs in this, that sugar 

 is constant and is not made more significant by the presence of large 

 quantities. 



