Ash in Urine. 



357 



eliminated. It is very much to be regretted that complete proximate analyses 

 of urine could not have been made, as such data would undoubtedly make much 

 clearer many troublesome points which arise in interpreting the results of the 

 partial urinary analyses that were possible. 



Ash. In addition to the total solids, the ash was determined by incinerating 

 the dried material at as low a temperature as possible, extracting the charred 

 mass with water, and igniting the carbonaceous material. The aqueous extract 

 was evaporated to small bulk, added to the ignited residue, and after com- 

 pleting the evaporation, the mass was dried for a few moments at a low red. 

 heat. Admittedly the errors in this determination are such as to make it 

 only approximate, and the results are valuable only for the purposes of 

 comparison, but since the same method was followed with all experiments, 

 comparisons probably have more value than would be the case if different, 

 though even more accurate methods, had been employed to determine the total 

 solids and ash in the different experiments. The quantities of total solids are 

 recorded in column g of table 193. The total ash as determined is recorded in 

 table 194. 



1 Not determined for individual days, calculated as shown on p. 28. 



2 Includes amount calculated in urine spilled. See p. 243. 



As has been pointed out before, the ash in experiments Nos. 59 and 68, 

 was apportioned over the different days, and hence the figures do not represent 

 actual determinations. In all subsequent experiments, the ash and total solids 

 for each day were determined. 



Delaying for the present the discussion of the constituents of ash, the 

 total ash determinations are of value in showing what proportion of the total 



