372 THE METABOLISM OF THE CARBOHYDRATES 



been found to be the case, although all the excess of ammonia 

 cannot thus be made to disappear (Magnus Levy). 



The percentage of carbonic acid in diabetic blood, especially 

 during coma, is stated to be very small ; thus Minkowski ( 2s ) found 

 only 3*3 vols. per cent, in one case of diabetic coma shortly before 

 death, and 15 per cent, in another case at the beginning of the 

 coma, and a normal amount in two cases of severe diabetes not in 

 the comatous state (Naunyn 31 ). Kraus found 6-4 vols. per cent. 

 (vide Magnus Levy 30 ). 



The alkalinity of the blood is likewise said to be diminished in 

 diabetic coma. According to Kraus the normal alkalinity corre- 

 sponds to 185-220 m.g. NaOH for 100 c.c. blood, whereas in 

 diabetic coma it was found to be 125 m.g. NaOH. 



The fact that the administration of alkali increases the excretion 

 of acid in the urine would further corroborate the idea that an 

 acid intoxication exists. Beddard, Pembrey, and Spriggs ( 42 ) have 

 recently reported some determinations of the alkalinity and C0 2 - 

 content of the venous blood of diabetics : they have found that a 

 rise or fall in the one is accompanied by a rise or fall in the 

 other, but that a strict parallelism between the two does not 

 exist. During diabetic coma the percentage of C0 2 in the alveolar 

 air was found to be much below the normal. They conclude that 

 the diminished C0 2 -content of the venous blood in diabetic coma 

 is the result of the hypernoea (i.e. of the increased ventilation of 

 the lungs) rather than its cause. 1 This conclusion is based not 

 only on the observations detailed above, but also on certain 

 experiments which, however, cannot be given here. 



The source of the (B-oxy -butyric acid and its oxidation products is 

 somewhat obscure. It cannot be derived from proteid, as the 

 following observations show : in the urine of three days from a 

 case of diabetic coma Magnus Levy ( 30 ) was able to separate 

 326 grm. /3-oxy-butyric acid, and the nitrogen excretion showed that 

 meanwhile 271 grm. proteid had undergone metabolism in the 

 organism. There was an excess of /3-oxy-butyric acid alone, to say 

 nothing of the aceto-acetic acid and acetone which had also been 

 excreted. Nor is it conceivable that all the carbon of proteid 

 could have been thus excreted. This does not of course preclude 



1 They found the blood of a diabetic (in coma) could take up a normal 

 amount of C0 2 on exposure to an atmosphere of this gas. The coma causes 

 lessened production of COo. (Editor.) 



