592 



GENERAL METABOLISM. 



[CH. XXXIX. 



Increased output of carbonic acid also occurs in fever. 



Other changes noted in fever are a rapid loss of the liver 

 glycogen, a lessening of chlorides in the urine, and often an 

 increase of the urobiliu in the urine. 



The following table illustrates exchange of material in fever, 

 no food being taken : 



Compare this table with that at the bottom of p. 587. 



Diabetes mellitus. In addition to the presence of sugar in the 

 urine in this disease, the most marked symptoms are intense 

 thirst and ravenous hunger. As a rule diabetic patients digest 

 their food well. The thirst is an indication of the necessity of 

 replacing the large quantities of water lost by the kidneys ; the 

 hunger, that of replacing the great waste of tissues that occurs. 

 For not only does the urine contain sugar, but, in addition, a 

 great excess of urea and uric acid. The carbonic acid output is 

 somewhat smaller than in health. In health the carbohydrates, 

 after assimilation, give rise, by oxidation, to carbonic acid ; in 

 diabetes, all the carbohydrates do not undergo this change, but 

 pass as sugar into the urine. Not that all the sugar of the urine 

 is derived from carbohydrates, for many diabetics continue to pass 

 large quantities when all carbohydrate food is withheld ; under 

 these circumstances, it must be derived from the destruction of 

 proteid matter (see also pp. 510, 567). 



Luxus Consumption. 



In former portions of this book we have insisted on the fact 

 that the food does not undergo combustion, or katabolic changes, 

 until after it is assimilated, that is, until after it has become an 

 integral part of the tissues. Formerly the blood was supposed 

 to be the seat of oxidation ; but the reasons why this view is not 

 held now have been already given. When a student is first con- 

 fronted with balance-sheets, representing metabolic exchanges, it 



