4G0 Influence of Inanition on Metabolism. 



The excretion of neutral sulphur parallels in a marked manner that of pre- 

 formed creatinine. While Folin is inclined, according to recent statements, 140 

 to regard the excretion of neutral sulphur in a somewhat different light than 

 when he enunciated his theory of protein metabolism, it is significant that, 

 in fasting experiments, the excretion of preformed creatinine and neutral 

 sulphur should decrease as the fast progresses at practically the same rate. 

 But one explanation for this phenomenon appears at present. Possibly dur- 

 ing the earlier stages of fasting, the fluid proteins are first drawn upon. This 

 represents a condition of katabolism not unlike that during the ordinary 

 digestion of food. It may be measured by the total creatinine and the neutral 

 sulphur output. The body becomes depleted of its fluid protein as the fast 

 continues, and then the muscle is disintegrated and the creatine in the flesh 

 katabolized is set free. Under ordinary conditions the body may cleave the 

 protein molecule to creatinine during the process of katabolism, but be unable 

 to dehydrate preformed creatine to creatinine. On this assumption it would 

 appear that the preformed creatine existing in the muscles does not undergo 

 any katabolism, that it is a relatively constant quantity and only when actual 

 muscle substance is drawn upon, as during inanition, is it excreted as such. 



The remarkable constancy of the total creatinine excretion as the fast pro- 

 gresses does not justify final conclusions regarding the excretion of creatine in 

 flesh katabolized during the later clays of fasting. It would seem more than 

 a coincidence that the amount of creatinine resulting from endogenous protein 

 katabolism plus the amount of creatine in flesh katabolized should remain 

 constant during the whole of the 7-day fast. 



Eecently Lichtenfelt, 147 observing the influence of inanition upon the com- 

 position of fish muscle, found that the muscle became richer in water when 

 due allowance was made for the loss of fat and protein. 



This observation, likewise, is of interest in connection with the older 

 assumption that when flesh was katabolized the water in it was liberated and 

 excreted. According to Lichtenfelt the water is not necessarily eliminated, 

 but the muscle has a higher water content. 



While Lichtenfelt's results indicate that there may be a loss of protein from 

 muscle, Abderhalden, Bergell & Dorpinghaus 148 found on investigating the 

 proteids of the blood and the body, by the esterfication method, that there 

 was no difference to be observed when comparing the determinations on animals 

 in health and animals after inanition, thus showing that the residual protein 

 had not been altered as a result of inanition. 



While undoubtedly a portion of the katabolized protein is that of muscle, a 

 significant fraction is in all probability derived from some of the larger organs. 



14a Extract from a personal letter cited by Shaffer, Amer. Journ. of Physiol. (1906), 

 16, p. 274. 



u7 Archiv f. d. ges. Physiol. (1904), 103, p. 402. 

 ltt Zeit. f. physiol. Chem. (1904), 41, p. 153. 



