574 PHYSIOLOGICAL CHEMISTRY 



following day, i.e., the third day of the experiment. At that time ingest 125-150 

 grams of gluten or some other purine-free protein preparation. On the fourth 

 day of the experiment eat nothing until 9 P. M. 



Collect the urine each day hi hour periods from 7 A. M. to 9 P. M. and analyze 

 for uric acid (see methods hi Chapter XXVI). Chart your data similarly to 

 those shown in Figs. 170 and 171, page 573, and compare them with the findings 

 there recorded. 



10. The Rate of Purine Excretion. The purine material ingested 

 by the average normal person and which is not transformed in the body 

 will be eliminated in about 24 hours. In the case of persons afflicted 

 with gout the purine elimination is delayed. The establishment of this 

 delayed purine elimination is often of diagnostic assistance. 



Demonstrate the rate of purine excretion as follows : Ingest a purine-free 

 diet consisting of egg, milk, cheese, starch, sugar, fruit and water for two days and 

 follow this by a day in which sweetbreads, thymus or liver is substituted for one 

 of the meals of the day (see table page 572 for purine content of foods). Finish 

 the experiment by ingesting the original purine-free diet for two days. Collect 

 each day's urine and analyze for uric acid. How soon after the sweetbread 

 ingestion was the original plane of endogenous uric acid elimination reestab- 

 lished? If one desires to locate this time more definitely the urine may be 

 collected in short periods (one to two hours) and the uric acid content of each 

 specimen determined. Particularly instructive data may be collected by per- 

 forming the above experiment on a gout patient and upon a normal person for 

 comparison. 



11. A Study of Creatinine Elimination. It has been established 

 that a normal person ingesting a creatinine-free diet will excrete a uni- 

 form quantity of creatinine from day to day. The daily excretion of an 

 adult man of average weight ranges from 1-1.5 grams. For data as to 

 creatinine excretion of a 60 kg. man see Taylor and Rose's figures in 

 table on page 572. The creatinine excretion depends primarily on the 

 active mass of protoplasmic tissue, and therefore, it is generally true 

 that a fat man will show a lower creatinine output than a lean man of 

 like body weight. For further discussion of creatinine see Chapter XXII. 



Experiment. Ingest an ordinary mixed diet (non-meat) for a period of three 

 days varying the character of the diet daily. Collect the urine and analyze for 

 creatinine. (See Chapter XXVI for methods of analysis.) 



Did the creatinine elimination change with the change in diet? 



12. Influence of Water. It has been demonstrated that increased 

 water ingestion influences many of the functions and activities of the 

 human body. 1 The increase in protein catabolism which accomp- 

 anies high-water intake is shown in the following data collected from 



1 Hawk: The relationship of water to certain life processes and more especially to nu- 

 trition. Read before American Philosophical Society, Philadelphia, Feb., 1914. (See 

 Bioch, Bull., 3, 420, 1914). 



