METABOLISM OF CARBO-HYDRATES GLYCOSURI AS 555 



although oatmeal and potatoes are said to occupy an exceptional 

 position, and have even been recommended as beneficial. Calcium 

 chloride has been stated to diminish the sugar excretion in diabetes 

 (Boigey), and it has a similar effect in certain of the artificial glyco- 

 surias (Brown, Fischer). 



In many cases, even when carbo-hydrates are completely, or 

 almost completely, omitted from the food, sugar, derived from the 

 breaking-down of proteins, and possibly to some extent from fats, 

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

 products formed or imperfectly transformed in the deranged meta- 

 bolism, especially of fats, such as acetone, aceto-acetic acid, and 

 oxybutyric acid (the so-called acetone bodies), may also appear in the 

 urine (ketonuria), 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. The small amount of carbon dioxide in 

 the venous blood may also be partly due to the hyperpnoea, marked 

 by increased depth of the respiratory movements produced by 

 stimulation of the respiratory centre by other substances than carbon 

 dioxide. The increased ventilation causes a fall in the carbon 

 dioxide pressure in the alveolar air, and therefore an increased 

 elimination of that gas from the blood. This form of coma appears 

 to be really in part 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 proteins. The ad- 

 ministration 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, 

 and in some cases i.t is successful in staving it off for a time. Often, 

 however, in spite of a prolonged course of treatment, during which 

 the urine has continued distinctly alkaline, fatal coma eventually 

 occurs. The coma then is not merely a symptom of acidosis, 

 but is also due to the specific toxic effects of the acids even when 

 neutralized. Other toxic products may also be formed in the 

 deranged metabolism. The appearance of the acetone bodies in 

 diabetes presents a problem which cannot be said to have been as 

 yet completely solved. Oxybutyric acid, from which aceto-acetic 

 acid and acetone are easily derived (p. 567), seems to be one of the 

 intermediate steps in the normal metabolism of fats. But whereas 

 under ordinary circumstances it is readily oxidized in the body, in 

 diabetes the power of the tissues to burn oxybutyric acid seems to 

 suffer just as does the power to utilize dextrose. The suggestion 

 that in diabetes the abnormally great consumption of fat entailed by 

 the loss of availability on the part of the carbo-hydrates causes the 

 intermediary metabolism of fats to be scamped, as it were, is not 

 satisfactory. For many animals and some races of men dwelling 



