PHYSIOLOGICAL CHEMISTRY 



claims that camphor is a very satisfactory urine preservative which 

 does not interfere with the tests for important urinary constituents. 



In certain pathological conditions it is desirable to collect the urine 

 passed during the day separately from that passed during the night. 

 When this is done the urine voided between 8 A. M. and 8 P. M. may 

 be ta'ken as the day sample and that voided between 8 P. M. and 8 A. M. 

 as the night sample. 



The qualitative testing of urine samples collected at random, except 

 in a few specific instances, is of no particular value so far as giving us 

 any accurate knowledge as to the exact urinary characteristics of the 

 individual is concerned. In the great majority of cases the qualitative 

 as well as the quantitative tests should be made upon the mixed 

 excretion for a twenty-four-hour period as well as upon a night sample 

 as ^above described. 



