84 DONALD D. VAN SLYKE 



as the square of the fall in plasma bicarbonate below the point indicated 

 by 80 volumes per cent of CO 2 as indicated by the equation 



/ 80 plasma CO 2 \ 2 

 0.1 N acid + N1I 3 per kilo body weight = I - \ 



The clinical significance of varying excretion rates in at least this 

 one form of acidosis (diabetic) is indicated by Table II. In diabetes the 

 excretion follows the fall in alkaline reserve with sufficient regularity to 

 form a semi-quantitative measure of the latter. 



In nephritis the ammonia plus acid excretion appears to bear no rela- 

 tion to the alkali reserve. 



Determination of Acetone Bodies in the Blood and Urine 



In diabetes and apparently also in fasting and in the cyclic vomiting 

 of children, acidoses occur which are entirely due to rapid formation of 

 the "acetone bodies/' (Miydroxybutyric acid, and acetoacetic acids. Their 

 source is incompletely burned fatty-acids, and in diabetes 36 per cent of 

 the fat consumed may be excreted as acetone bodies (Magnus-Levy, 1905). 

 Their formation, in diabetes at least, is attributed by Magnus-Levy to 

 combustion of fatty acids without the simultaneous combustion of suffi- 

 cient carbohydrate, the latter being necessary, for some still unexplained 

 reason, to complete combustion of the fats. Ladd and Palmer (1921) 

 have confirmed this explanation. They find that acetone bodies are formed 

 by diabetics as by normal persons, when the ratio of calories fat to calories 

 carbohydrate burned exceeds about 10 to 1, so that the cause of ketonuria 

 in diabetes is not primarily failure in the fat-burning mechanism, but 

 secondary failure in fat combustion due primarily to failure in sugar 

 combustion. The acidosis of fasting has the same origin ; the body con- 

 sumes its carbohydrate so rapidly that after a short fast it no longer 

 has sufficient to supply the necessary 1 to 10 ratio for the combustion of 

 fat. The ketonuria of the toxemias of pregnancy is presumably due to 

 fasting (Van Slyke and Losee, 1917), and has been shown by Duncan and 

 Harding (1918) to be remedied by administration of lactose. 



In cyclic vomiting of children, however, ketonuria occurs without previ- 

 ous evidence of malnutrition, and we are entirely ignorant of its primary 

 metabolic cause. 



Ketone formation has two significances: it indicates incomplete fatty 

 acid combustion; and it indicates the formation of acid products which 

 may lead to an abnormal state in the acid-base balance of the body. 



Quantitative determinations of the acetone bodies in the urine (Van 

 Slyke(e), 1917) and blood (Van Slyke and Fitz(a)(6), 1917 and 1919) 

 are chiefly of value to indicate the extent, of the failure in fatty acid metab- 

 olism and to assist in its dietary control. They do not indicate very 



