METABOLISM, NUTRITION AND DIETETICS 453 



In the natural diabetes of man it is possible that in some cases 

 the sugar coming from the alimentary canal passes entirely or in too 

 large amount through the liver, owing to a deficiency in its power of 

 forming glycogen. But although in certain cases of diabetes speci- 

 mens of the hepatic cells, obtained by plunging a trocar into the 

 liver, have been found free from glycogen, in others glycogen has 

 been present. And it is remarkable that levulose may be entirely 

 used up in the tissues of a diabetic patient, or of a dog rendered 

 diabetic by extirpation of the pancreas, while dextrose, which is so 

 closely allied to it, and from which an identical form of glycogen is 

 produced, is promptly cast out by the kidneys. In many cases even 

 when carbo-hydrates are completely, or almost completely, omitted 

 from the food, sugar, derived from the breaking-down of proteids, 

 still continues to be excreted, although in smaller quantity. Other 

 products of the deranged metabolism of proteids or of fats, such as 

 acetone, aceto-acetic acid, and oxybutyric acid, may also appear in 

 the urine, or, accumulating in the blood, may, by uniting with its 

 alkalies, seriously diminish the quantity of carbon dioxide which that 

 liquid is capable of carrying, and thus lead to the condition known 

 as diabetic coma. This form of coma appears to be really an acid- 

 poisoning comparable to the condition produced in animals by doses 

 of mineral acids too large to be neutralized by the ammonia split off 

 from the proteids. The administration of very large doses of alkalies 

 (sodium bicarbonate, for instance, to the amount even of hundreds 

 of grammes) has been recommended for the treatment of this serious 

 complication. The most rational way of explaining many of the 

 facts of diabetes is to suppose that, from some change in the tissue 

 elements, sugar has ceased to be a food for them, or is used up in 

 smaller amount than in the healthy body, while the actual production 

 of sugar is no greater than in a normal person with the same diet 

 and the same intensity of metabolism of substances other than carbo- 

 hydrates. 



Normal blood seems to contain a ferment which has the power of 

 destroying sugar and forming lactic acid ; and the statement of 

 Lupine and Barral that extirpation of the pancreas, which is followed 

 by diabetes, causes a diminution in the activity or in the amount of 

 this ferment, appeared to afford the basis for a theory of diabetes. 

 But Spitzer has asserted that the sugar-destroying power of blood 

 taken from diabetic patients, or from animals in which glycosuria 

 had been caused by phloridzin, is not at all inferior to that of healthy 

 blood. And, indeed, results that depend upon the determination of 

 minute differences in the quantity of sugar must be accepted with 

 reserve. 



3. Metabolism of Fat. The fat, passing along the thoracic 

 duct into the blood stream, is very soon removed from the 

 circulation, for normal blood contains only traces, except 

 during digestion. Where does it go ? What is its fate ? 



The presence of adipose tissue in the body might suggest 



