METABOLISM 565 



THE CELL 



PROTEIN,. FAT, \ ^ 

 CARBOHYDRATE 



COMBUSTION 



Without doubt both anabolic and catabolic processes are going on in- 

 cessantly within every individual living cell. At one time the anabolic 

 phase will be more prominent; at another the catabolic activity will be 

 in the ascendency. It should also be borne in mind that metabolism 

 implies a transformation of energy as well as an exchange of materials. 



For further brief discussions of certain phases of metabolism see 

 the following experiments. A detailed discussion being out of place 

 in this volume, the reader is referred to the following books : 



(1) Taylor's "Digestion and Metabolism," Lea and Febiger, 1912. 



(2) Sherman's " Chemistry of Food and Nutrition," Macmillan. 



(3) Osier & McCrae's "Modern Medicine," Vol. II, Second Edi- 

 tion, 1914, Lea and Febiger. The author's section on "General Con- 

 sideration of Metabolism," [pages 549-673. 



METABOLISM EXPERIMENTS 

 i . Metabolism Procedures Involving the Manipulation of the Urine 



1. Collection and Preservation of the Urine. In metabolism tests, 

 such as those given in this chapter the accurate collection of the urine 

 for the exact 24-hour period is of the utmost importance. Proceed as 

 follows: Empty the bladder at a given hour, e.g., 8 a.m. and discard the 

 urine. Prepare a thoroughly clean bottle of proper size, introduce into 

 it sufficient toluene to cover the bottom of the bottle and use this bottle 

 for the collection of all urine voided from 8 a.m. until 8 a.m. the next 

 day. During the day, when not actually in use for the introduction 

 of a urine fraction, the bottle should be kept in a refrigerator or cold 

 room in order that the sample may not deteriorate before it is examined. 

 Measure the volume of the sample and determine its specific gravity 

 (see Chapter XXI) and reaction before proceeding to the quantitative 

 estimation of any specific urinary constituents. 



2. Complete Analysis of Urine. Ingest an ordinary mixed diet (or any special 

 diet) and collect the urine accurately for a 24-hour period (see above). Measure 

 the volume of the sample, determine the specific gravity and preserve the urine 

 (see above) until the following constituents have been determined (for Methods 



