2/6 PHYSIOLOGICAL CHEMISTRY. 



ine elimination, expressed in milligrams per kilogram body weight, 

 is an index of this special process. 1 He further states that the mus- 

 cular efficiency of the individual depends upon the intensity of this 

 process. Under normal conditions about i gram of creatinine is ex- 

 creted by an adult man in 24 hours, 2 the exact amount depending 

 in great part upon the nature of the food and decreasing markedly 

 in starvation. Very little that is important is known regarding 

 the excretion of creatinine under pathological conditions. The 

 creatinine content of the urine is said to be increased in typhoid 

 fever, typhus, tetanus and pneumonia, and to be decreased in anaemia, 

 chlorosis, paralysis, muscular atrophy, advanced degeneration of 

 the kidneys, and in leucaemia (myelogenous, lymphatic and 

 pseudo). An increase of creatinine was also noted in diabetes, 

 an increase probably due to the creatinine content of the 

 meat eaten. The greater part of the data, however, relating to the 

 variation of the creatinine excretion under pathological conditions 

 are not of much value since in nearly every instance, the diet was not 

 sufficiently controlled to permit the collection of reliable data. And 

 further, until the advent of the Folin method (see p. 392), there 

 was no accurate method for the quantitative determination of cre- 

 atinine. Shaffer has very recently called attention to the fact that 

 a -low excretion of creatinine is found in the urine of a remarkably 

 large number of pathological subjects, representing a variety of con- 

 ditions, and that it is therefore evident that the excretion of an ab- 

 normally small amount of this substance is by no means peculiar to 

 any one disease. 



Creatinine crystallizes in colorless, glistening monoclinic prisms 

 (Fig. 90, p. 277) which are soluble in about 12 parts of cold water; 

 they are more soluble in warm water and in warm alcohol. One 

 of the most important and interesting of the compounds of creatin- 

 ine is creatinine-zinc chloride, (C 4 H 7 N 3 O) 2 ZnCl 2 , which is formed 

 from an alcoholic solution of creatinine upon treatment with zinc 

 chloride in acid solution. Creatinine has the power of reducing 

 cupric hydroxide in alkaline solution and in this way may interfere 

 with the determination of sugar in the urine. In the reduction by 

 creatinine the blue liquid is first changed to a yellow and the for- 

 mation of a brownish-red precipitate of cuprous oxide is brought 



1 He proposes to designate as the " creatinine coefficient " the excretion of 

 creatinine -nitrogen (mgs.) per kilogram of body weight. 



~ According to Shaffer the amount excreted by strictly normal individuals 

 is between 7 and n milligrams of creatinine-nitrogen per kilogram of body 

 weight. 



