Experimental Studies on Creatine and Creatinine. 127 
Thus they may be carried to or from adipose tissues, be deposited 
in the egg-yolk, or be secreted in company with fat in the milk 
of animals; they apparently do not traverse the placenta. The 
dyes have not been detected in the lipoids of the nervous tissue. 
We have failed to note any inability on the part of animals to 
utilize fats in which Sudan III. has been deposited. 
77 (602) 
Experimental studies on creatine and creatinine. 
By W. 0. ROSE. 
[From the Laboratory of Physiological Chemistry, Sheffield 
Scientific School, Yale University, New Haven, Conn.] 
The excretion of creatine induced by starvation in rabbits, 
is inhibited partially or completely by feeding a diet of carbo- 
hydrates alone. The creatine elimination is not reduced by 
feeding a diet of fat alone or by a diet of fat and protein. 
Experimental interference with carbohydrate metabolism leads 
to the elimination of creatine. After phlorhizin diabetes, which 
depletes the store of carbohydrates, and during phosphorus 
poisoning, which disturbs the glycogenic functions, the output of 
creatine in dogs is decidedly increased. 
An increase in the output of creatine plus creatinine (total 
creatinine) is always accompanied by an increase in total nitrogen 
elimination. This parallelism in inanition and with nitrogen-free 
diets, is ascribed to a common source, — namely, true tissue or 
endogenous metabolism. The metabolism of exogenous or reserve 
proteins is not accompanied by the production of creatine or 
creatinine. 
Coincident with the increased elimination of total creatinine 
during fasting, a significant increase in the creatine content of 
muscle occurs in rabbits and hens. This indicates an increased 
production of creatine during the accelerated catabolic processes. 
Creatine is a normal constituent of the urine of the young 
until the age of puberty. Possibly this is due to insufficient gly- 
cogenic functions. Though no direct evidence for such an assump- 
tion has been obtained, still the ease with which children develop 
