CREATINE. 139 



demonstrate the nutrient qualities of the former, it must be asked, 

 whether its occurrence in a substance so nourishing as the decoction 

 of flesh, and its large amount of nitrogen, afford more conclusive 

 evidence in this respect ? With reference to the latter, it may be 

 assumed that nature would not suffer substances even more highly 

 nitrogenised than creatine, as the creatinine discovered by Liebig in 

 the urine and the urea, to escape through the kidneys, if they could 

 be employed to further advantage in the organism, since we find so 

 careful a providence over recognised nutrient matters, as for 

 instance, albumen, &c., that even in disease they are only rarely 

 found to escape with the excreta. The occurrence of creatine in the 

 decoction of flesh affords even less evidence of its nutrient powers, 

 for when we consider the small quantity in which it occurs in flesh, 

 and the truly homoeopathic nature of the dose which we take with 

 the meat and broth we eat, we must regard its simultaneous 

 appearance in the urine as a proof that its properties are not very 

 highly esteemed in the organism, since, if they were so, this sub- 

 stance would probably not be discharged from the kidneys, but be 

 retained in the same manner as albumen and gelatin. We think, 

 however, that Liebig's complete chemical investigations of creatine, 

 which were conducted in a manner worthy of so great a chemist, 

 constrain us, even if unsupported by physiological proof, to regard 

 creatine as a product of excretion. From its chemical qualities we 

 regard creatine a member of the series indicating the regressive 

 metamorphosis from the point of the highest atomic weights to 

 bodies of the simplest composition. The readiness with which 

 creatine becomes decomposed into creatinine, urea, and sarcosine, 

 which is isomeric with lactamide, all of which are undoubtedly 

 products of excretion, proves beyond a doubt, that creatine 

 approximates more nearly to these substances than to albumen 

 and fibrin, and indicates the great probability of creatine being 

 decomposed even in the living body into these and other similar 

 substances. Although such bodies as lactic acid, &c., may be 

 employed for special purposes in the animal organism, they cannot, 

 strictly speaking, be regarded as nutrient substances, that is to say, 

 as materials for the renovation of nitrogenous tissues; and it is 

 only in this light, and not in that of a supporter of heat, that we 

 must consider creatine. Creatine is, however, a substance of the 

 highest importance in relation to physiological chemistry, as it 

 affords us a glimpse at the ever-recurring chemical changes which 

 are associated with the functions of organs, and of which we have 

 at present so little general knowledge. 



