FORMATION OF SUGAR. 391 



The formation of sugar from fat seems to occur in the plant king- 

 dom, and as the chemical processes in the animal and plant life are in 

 principle the same, it makes the possibility of a sugar formation from 

 fat very probable. Such an origin of sugar in the animal body is accepted 

 by many investigators, especially by PFLUGER and several French 

 observers, among whom we must specially mention CHAUVEAU and 



KAUFMANN. 1 



When food as free from carbohydrate as possible is taken, the quo-* 

 tient D:N is high, i.e., higher than 8, as well as when the quantity of 

 sugar is so large that it cannot be accounted for by the calculated 

 protein (and carbohydrate) metabolism, then if the observations are other- 

 wise free from error we can admit of a formation of sugar from fat. Sev- 

 eral such cases of diabetes in man have been published (RUMPF, ROSEN- 

 <JVJST, MOHR, v. NOORDEN, ALLARD, FALTA and co-workers and others), 

 and also in animals (HARTOGH and ScHUMM 2 ) . Although these researches 

 are not fully conclusive, still certain of them indicate a probable forma- 

 tion of sugar from fat. We also have several conditions which indicate 

 the same, namely, that in phlorhizin diabetes after the disappearance 

 of the liver-glycogen the fat which migrates to the liver serves as mate- 

 rial for the formation of sugar (PFLUGER) ; still this is not sufficient for 

 a positive proof. 



On the other hand there are also many observations on animals and 

 also clinical observations which oppose the theory of the formation of sugar 

 from fat in diabetes. LUSK found in a dog with phlorhizin diabetes 

 that the quotient D:N=3.65:1 was not changed on feeding fat, and he 

 has recently published results of experiments 3 which show that active 

 muscular work, which strongly increases the fat decomposition, does not 

 change, the quotient in dogs with phlorhizin diabetes. It is difficult to 

 draw positive conclusions from these experiments, still LUSK seems to 

 deny the formation of sugar from fat. 



Attempts have been made to solve the question as to the material from 

 which sugar is formed by the determination of the respiratory quotient 

 and comparing this with the quotient D:N. The calculations in this 

 direction have not led to positive results. 4 As the quotient D:N 



1 Kaufmann, Arch. f. Physiol. (5), 8, where Chauveau's work is cited. 



2 Rumpf, Berl. klin. Wochenschr., 1899; Rosenqvist, ibid.; Mohr, ibid., 1901; v. 

 Noorden, Die Zuckerkrankheit, 3. Aufl., Berlin, 1901; Allard, Arch. f. exp. Path. u. 

 Pharm., 57; Falta and co-workers, Zeitschr. f. klin. Med., 66; Hartogh and Schumm, 

 Arch. f. Path. u. Pharm., 45. See also the works of O. Loewi, ibid., 47, and Lusk, 

 Zeitschr. f. Biologic, 42. 



3 Amer. Journ. of Physiol., 22. 



4 Magnus-Levy, Zeitschr. f. klin. Med., 56; Pfluger, Pfliiger's Arch., 108; Mohr, 

 Zeitschr. f. exp. Path. u. Therap., 4. 



