The subject :innouriced for this lecture-" the rdlc of clicarbosylic ncids in nictabolisin "-has become very estensive i n the course of tlic last few years. There can be no question of a more or less complete trcatmciit of this subject in the liniited time a t ~n y disposal. I have therefore had to make a clioicc among the iivailable inaterial and i t will not be surprising that this has principally fallen on investigations with which I have been personally connected. Up to a short time xigo these rclnted especially to fat catabolism. Our work in this field forms a suitable starting point for my csposi tion.
It is at present practically generally accepted that tlic degradation of tiorinn1 saturated fatty iicids itt vivo e m take place by w-ozidalion and subsequent lifuteral F-ojcidulio~ of the dicarbosylic iicid protluccd besides by the classical way of torilateral F-o.cid(ifioti discovered by Kxioop. In nip view our present certain knowledge of the catabolisni of thesc iicids caii be suniinnrized in t,he following scheme : 0 CH,*(CH:)11.C00)1 + HOOC.(CH~),~*COOH Y l a Y l a w Y l a (0 ctc.
-3 otc. The extremely important r61c which the F-osidation playe here is noteworthy. The o-oxidation ciili be considered 11s i t were ns an efficiency mensure of the organism, whcrel)y tlic iiiolccule obtiiiits ii fresh point of attack for the F-oxidation.
Our nccitlcntul discovery of dioic ucitl-rtcidosis rind rliuciditria in tnan nfter adttiittistration of tiiundecylinl was the i tiitnediate cause for coniposing the above schenie ; undccancdioic acid (CIJ and, to a niuch sinriller degree, Iionirticdioic mid (=n~cloic iicid) (C,) arid hcptanedioic acid (=pitiiclic iicid) (C,) proved to be excreted in the urine as a consequence of iiti iiccut~t~~lritio~i of these ncids in the blood.2 An investigrition of tlic hehuviour OF a series of simple triglyccritles derived from iiorlnnl saturated fatty acids with odd rind even numbers of cnrbon atonis subsequently leiid to n very wmnrknblc result.3 1 t nppciircd that iidnii~iistriitioii of these substances to oiic iind the saiiic subject uittlcr 1,ccturo delivcrcd in Jliircli, 1038, ut University C!ollqp, Lpntlon, UriiverNity Colicgc, Nottingliuui, nnd tlic Uniwrsity of Imcrpool. 11s frir as possi1)le the same conditions gives rise to dioic acid-ncidosis ntid dincidiiriri to very diffcrerit degrees ; in other words, tlicsc triglyccrides appeared to have very different tliacitlogctt ic p -o ~~e r ~i c s .
A comparative review of the 1)chtiviour of the triglyccritlcs then invcstigated looks as follows :
C, tricnpryliii \i'cukly