HISTORY OF DIFFERENT FOODSTUFFS IN BODY 1043 



agreement with which the conversion of the glucose into glycogen, as 

 well as the conversion of the latter into the former substance, is 

 determined by the amounts of glucose in the blood available for pur- 

 poses of oxidation. It cannot be doubted that this process is actually 

 at work, but obviously, the fact that it takes place does not offer an 

 explanation for the manner in which it is accomplished. The second 

 possibility finds its basis in the fact that such products as lactic acid 

 and carbon dioxid are circulating in the blood and change the hydro- 

 gen ion concentration of the blood, thereby exciting a glycogenolysis. 

 The third possibility, that this regulation is effected by means of a hor- 

 mone secreted by some ductless gland, possesses a sound experimental 

 basis. Chief among these internal secretory organs is the pancreas, 

 then follow the adrenals, parathyroids and pituitary. 



We have previously noted that the hyperglycemia and glycosuria, 

 following the removal of the pancreas, are due to the loss of an internal 

 agent which makes the sugar immediately available for oxidation by 

 the tissue cells. The other glands, in all probability, act in an indirect 

 way through the nervous system, increasing glycogenolysis. These 

 two conditions, therefore, would give rise to the so-called pancreatic 

 and hepatic types of glycosuria. The temporary alimentary type is, 

 of course, dependent upon an increased absorption of sugar and an 

 overburdening of the system with this substance. A fourth method of 

 producing glycosuria has been discovered by Mering. 1 It has been 

 used extensively by Lusk, 2 and consists in the administration of a 

 glucoside, known as phloridzin, which is derived from the bark of the 

 roots of the apple, cherry and pear trees. It produces a glycosuria 

 in spite of the fact that the sugar content of the blood may be below 

 normal. This shows that this type of glycosuria must be due pri- 

 marily to a leakage of the sugar through the kidneys in consequence of 

 an injurious action of this substance upon the renal epithelium. Phlor- 

 idzin-glycosuria, therefore, is a type of renal glycosuria. The tempo- 

 rary glycosuria which may be developed in consequence of nervous 

 excitement is in all probability to be classified as a disorder of glyco- 

 genesis and glycogenolysis. 



It will now be seen that the condition of acidosis cannot be attrib- 

 uted exclusively to a disarrangement of the carbohydrate metabolism, 

 because the bodies causing this disturbance are aceto-acetic and /3- 

 oxybutyric acid, which are the oxidation products of acetone and the 

 fatty acids. When these substances accumulate in the course of dia- 

 betes mellitus, the condition is known as ketosis. It appears to be due 

 to the fact that the fats cannot be burned up thoroughly unless their 

 combustion is stimulated by the heat derived from oxidizing sugar. 

 In the absence of this heat, the fats are imperfectly reduced. Conse- 



1 Verhandl. des Kongr. fur inn. Medizin, vi, 1887, and Zeitschr. fur klin. 

 Med., 1889. 



2 Zeitschr. fur Biol., xlii, 1904, 31. 



