ACID INTOXICATION, DIABETIC COMA 453 



which is diacetic acid (being two molecules of acetic acid 

 united to each other, as follows) : 



CH 3 CO | OH Hj H 2 C COOH. 



Diacetic acid is, in turn, readily deprived of its COOH group 

 through oxidation, forming acetone, 



CH 3 CO CH 3 . 



All these reactions are readily accomplished in the labora- 

 tory, and we have good reason for believing that they normally 

 occur in the same way in the animal body. (Because of their 

 chemical relation these substances are often referred to collect- 

 ively as the " acetone bodies "). As long as a diabetic is main- 

 taining a good metabolic equilibrium the urine is free from both 

 acids, although small amounts of acetone (traces of which 

 under 0.02 grn. per day occur in normal urine l ) may be present ; 

 but when wasting sets in the two acids appear, combined largely 

 with ammonia, but partly with mineral bases. Normally but 

 2 to 5 per cent, of the nitrogen of the urine is in the form of 

 ammonia, but in diabetic acidosis the proportion may reach 

 from 10 to 25 per cent., the amount of urea being correspond- 

 ingly reduced. 2 



The presence of large quantities of these acids in the urine 

 presages coma, during which the amount of oxybutyric acid 

 often reaches 15-20 grams per day, and has been known to 

 reach 150 grams (Kiilz claimed to have found 226 grams). 

 Diacetic acid appears in relatively small amounts, rarely exceed- 

 ing 10 per cent, of the total organic acids of the urine. When 

 oxybutyric acid is present the other two substances are always 

 present, 3 but the converse is not true. In the development of 

 acetonuria, acetone is the first of the three bodies to appear ; 

 when 0.4 to 0.5 gm. of acetone is present in the day's urine 

 diacetic acid may be found, but oxybutyric acid does not usually 

 appear until the amount of acetone exceeds 1 gram. After 

 this the chief increase is in the oxybutyric acid, which often 

 reaches 30 to 80 grams, whereas the diacetic acid and acetone 

 together rarely exceed 7 to 8 grams (v. Noorden). In the 

 internal organs the acetone bodies may also be detected. Geel- 

 muyden 4 found that the organs of diabetics contain consider- 



1 Concerning normal occurrence of acetone in blood and tissues, see Halpern 

 and Landau, Zeit. exp. Path. u. Ther., July, 1906, Bd. 3. 



2 According to Edie and Whitley (Biochemical Jour., 1906 (1), 11), ad- 

 ministration of excessive amounts of alkali causes, conversely, elimination of 

 increased amounts of organic acids. 



3 See Pavy, Lancet, 1902 (U). 64 el. scq. (general review). 

 *Zeit. physiol. Chem., 1904 (41), 128. 



