774 URINE. 



been found between the fat consumed and the acetone bodies eliminated. 

 Certain investigators (GEELMUYDEN, SCHWARZ, WALDVOGEL x ) have 

 also observed an increase in the acetonuria on partaking of fatty food, 

 and at the present time the fats are considered as the most important 

 source of the acetone bodies. 



The three acetone bodies occurring in the urine, as above stated, are 

 acetone, acetoacetic acid and /9-oxybutyric acid, and this last is considered 

 as the mother-substance of the other two. If /?-oxybutyric acid, 

 CH 3 .CHOH.CH 2 .COOH, is introduced into the animal body, it is burnt 

 if the quantity is not too great, while if in excess it passes into the urine 

 as acetoacetic acid, CH 3 .CO.CH 2 .COOH. This acid can also be burnt, 

 but if large quantities are introduced it appears in part in the urine and 

 readily splits into acetone, CH 3 .CO.CH 3 , and CO2. Acetone is in part 

 burnt in the animal body, but a part is eliminated by the kidneys and 

 especially by the lungs. We can imagine that the /?-oxybutyric acid is 

 a physiological metabolic product which normally is completely changed 

 into acetoacetic acid and acetone, and in diabetes and especially with 

 lack of carbohydrates is formed to an increased extent, or its combustion 

 made more difficult, so that in the first place acetone and acetoacetic acid 

 pass into the urine and in severe cases also /?-oxybutyric acid (acidosis). 



That acetone bodies can be formed from proteins is shown by the 

 perfusion experiments of EMBDEN and ENGEL with livers and leucine, 

 where acetone is formed in the liver with acetoacetic acid as intermediary 

 body. It is also probable, in correspondence with the observations of 

 BAER and BLUM, 2 that in diabetics leucine and isovalerianic acid cause an 

 increase in the elimination of /9-oxybutyric acid, and that /?-oxybutyric acid 



CH 3X 

 is formed from leucine, with isovaleric acid, )>CH.CH 2 COOH, as 



CH/ 



intermediary step. In the formation of acetone from tyrosine and 

 phenylalanine, acetoacetic acid is formed as an intermediary, and probably 

 also /?-oxy butyric acid (EMBDEN and ENGEL). 



In regard to the formation of acetone bodies from fat it must be 

 remarked that glycerin has an antiketoplastic action and that the 

 fatty acids can only be considered. As to the behavior of these in the 

 formation of acetone, EMBDEN and MARX 3 have shown that only those 

 normal fatty acids which contain an even number of carbon atoms are 

 acetone formers, while those with an uneven number of carbon atoms 



1 Magnus-Levy, Arch. f. exp. Path. u. Pharm., 42; Geelmuyden, 1. c., and Norsk, 

 Magazin for Laegevidenskaben, 1900, see also Zeitschr. f. physiol. Chem., 41, Schwarz, 

 Deutsch. Arch. f. klin. Med., 1903; Waldvogel, Centralbl. f. innere Med., 20. 



2 Arch. f. exp. Path. u. Pharm., 55 and 56; Embden and Engel, Hofmeister's Bei- 

 tra-e, 11. 



3 Hofmeister's Beitrage. 11. 



