156 PHYSIOLOGICAL CHEMISTRY 



Physical Properties 



Volume. The excretion of the various urine constituents 

 varies considerably during the course of the 24 hour day. 

 Except in the case of some pathological constituents, the mere 

 presence of which is an indication of an abnormal condition, it 

 is customary to make analysis of, and report the amounts of the 

 substances found in the urine voided during a complete 24 

 hour period. Such a 24 hour specimen is most conveniently col- 

 lected by discarding the first voiding in the morning, then col- 

 lecting all urine voided during the day, and the first voiding of 

 the following morning. The specimen should be preserved from 

 spoiling by adding 5-10 c.c. of a 5% thymol solution in chloro- 

 form. 



The volume of such a sample varies through fairly wide 

 limits. It is determined by the balance between the amount of 

 water taken, and that excreted in other ways. Thus, loss by 

 excessive sweating, by diarrhea, or vomiting, or in fever where 

 evaporation from the skin is increased will cause a fall in the 

 urine volume. On the other hand, drinking much water, or 

 prevention of loss through the skin as on humid days when 

 evaporation is low, will tend to increase the total volume of the 

 urine. An average figure for adult men is 1,000-1,200 c.c. per 

 day, in women somewhat less, but the volume from a perfectly 

 healthy subject may be much lower (400-500 c.c. or less) or much 

 higher (2 to three liters or more). Children excrete less urine 

 than adults, 600-700 c.c. being an average amount between the 

 ages of 3 and 7 or 8 years. A new born infant excreted 17 c.c. 

 the first day, and on the 6th day, 206 c.c. Vegetarians usually 

 excrete a small volume. 



In pathological conditions such as fevers, or in kidney affec- 

 tions, the volumes may greatly diminish (oliguria), or no urine 

 may be excreted at all. Such a condition is of course extreme. 

 In the various forms of diabetes the volume may be very large ; 

 even 10 liters per day and greater volumes have been reported. 

 Such a condition is known as polyuria. 



