<• {h'lKuivnh'ATi-: I'll) sKu.oav 6:v.) 



deficiency of that liypotlictical suhstancc derived iroiu the i)aiierea.s. 

 It is well known tliat acid may retard glj^cogen formation and hasten 

 glycojren hydrolysis. It would appear from the woi'k of Murlin and 

 Kramer" that alkali may inei'ease jrlucose utilization. The rate of 

 actual oxidation is influenced by the suj)i)ly of oxy<>:en, etc. The fol- 

 lowing may serve to suggest other factors. 



It mifiht 1)0 ooiu'oivcd tliat llu' cell coTilaiiicd nioleciUcs of a trhicolytic catalyst 

 or enzyme similar in its effects to metallic hydroxides, that jjlucose molecules as 

 fast as they entered the cells would come into collision with catalyst molecules, 

 perhaps combining witli tliem, and that as a result of the encounter the glucose 

 molecules would he dissociated into unsaturated frajjments or ions. From the mo- 

 ment of imion or dissociation they would cease to behave as glucose molecules. 

 Tlie unsaturated fragments might suhs('(|ueiitly sutler various fates, depending 

 ujion tlie cliaracter and quantities of various substances in tlie cell. Thus, some 

 might combine with oxygen to yield, finally, carbon dioxide and water. Others 

 might combine with each other to form polymers like glycogen, others again 

 undergo reduction to fat or molecular rearrangement to give lactic acid. The 

 relative quantities imdergoing those several changes, would depend upon the 

 relative quantities of H and OH ions, of available oxygen, salts, etc., foimd in the 

 various phases of the cell. This conception is based on that used by Nef to ex- 

 plain the behavior of sugars in alkaline solutions. For a concrete conception of 

 the dvnamics of a reaction between an organic substrate and catalyst the reader 

 is referred to Van Slyke's study of the enzyme urease.s 



The general principles outlined above may be illustrated by experi- 

 ments with timed intravenous injections of glucose. It has long been 

 known that if a comjiaratively large dose of glucose is injected rapidly 

 into a peripheral vein a marked glycosuria usually results. Pavy, 

 however, emphasized the fact that a material fraction of a dose so 

 given fails to be excreted and appears to be utilized. Doyon and 

 Du Fourt demonstrated that with a standard dose of gluco.se the per- 

 centages excreted and utilized respectively are influenced by the time 

 consumed in injection, the slower rates of injection causing lower per- 

 centage excretions and vice versa. Blumenthal chose a standard in- 

 jection time of about 10 seconds and varied the weight of sugar given 

 in that time. He found that a certain dose of glucose might be 

 injected into the ear vein of a rabbit without causing any glycosuria 

 at all. However, the maximum dose which could be so injected once 

 could not be repeated 15 minutes later without causing glycosuria. 

 He assumed from this that the first dose "sattirated" the tissues and 

 that fifteen minutes later the utilization of sugar had only resulted in 

 a partial desaturation. He, therefore, determined the dose of glucose 

 which might be injected repeatedly at 15 minute intervals for as long 

 as 3 hours without ever causing glycosuria. His figures varied be- 

 tween 0.6 and 1.3 gm. per kg. of body weight per hour. This he 

 termed the "utilization limit," whereas the largest dose which could 

 be given within 10 seconds once without causing glycosuria he called 

 the "saturation limit." The latter he placed at 0.8 gm. per kg. but 



7 Jour. Biol. Chem., 101 fi ^27), 490. 



8 Jour. Biol. Chem., 1014 (10), 141. 



