ORIGIN OF ACETONE BODIES 433 



after ingestion of dietary fat. 4 That this sequence does not 

 evince itself in a more striking manner is, in the au thor's 

 opinion, due to the fact that we are not always able to insure 

 an increased utilization of fat by increasing the ingestion of 

 fat, as the excess is generally simply deposited. Twice in 

 the course of these lectures (Chapter XVI, p. 392 and Chap- 

 ter XVII, p. 427) occasion has been taken to refer to the 

 important discoveries of F. Knoop and G. Embden which 

 indicate (with great probability, in the author's opinion) 

 that the catabolism of the normal fatty acids proceeds with 

 a two-by-two loss of carbon atoms from the carboxyl end. 

 It has been pointed out above that there are no essential 

 difficulties in the belief that, beginning with the higher fatty 

 acids, by a continuous shortening of the carbon chain we 

 finally obtain butyric acid, from which we get oxybutyric 

 acid, and from this then diacetic acid and acetone. 



CH, 



CH 2 CH 



CH 2 CH 2 CH, CH, CH, 



CH 2 CH 2 CH 2 CH.OH CO CH, 



CH 2 > CH 2 > CH 2 *> CH 2 > CH 2 > CO 



CH a CH, COOH COOH COOH CH,. 



CH 2 COOH 



COOH 



It is very well worth noting and is established by many 

 observations on diabetic human beings and animals 5 that 

 administration of butyric acid (C 4 ) and caproic acid (C 6 ) 



4 Geelmuyden; L. Schwarz; E. P. Joslin (Harvard Univ., Boston), Jour, 

 of Med. Research, 12, 433, cited in Biochem. Centralbl., 8, No. 828, 1904; 



E. Allard (Minkowski's Clinic, Greifswald), Arch. f. exper. Pathol., 57, 1, 1907; 



F. Steinitz, Centralbl. f. innere Med., 25, 81, 1904; Forssner (Stockholm), 

 Skandin. Arch., 23, 305, 1910; cf. therein the older Literature. 



6 Geelmuyden, Rumpf, L. Schwarz, Lob, Strauss and Philippsohn; cf. 

 Magnus-Levy, 1. c., p. 185; L. Schwarz (Prague), Deutsch. Arch. f. klin. Med., 

 76, 233, 1903; J. Bar and L. Blum (S'trassburg), Arch. f. exper. Pathol., 55, 89, 

 1906; 59, 321, 1908; 62, 129, 1910. 



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