352 The Philippine Journal of Science isis 



Undetermined nitrogen. — Undetermined nitrogen was calcu- 

 lated by subtracting from the total nitrogen the ammonia, urea, 

 uric acid, and creatinine nitrogen. Folin(7) has found that the 

 absolute quantity of undetermined nitrogen is indirectly propor- 

 tional to the protein intake and the total nitrogen. His average 

 figure for undetermined nitrogen on a high protein diet is 2.7 

 to 5.3 per cent of the total nitrogen, while in a low protein diet 

 it is 4.8 to 14.6 per cent of the total nitrogen. The average 

 undetermined nitrogen in the Filipino series was 1.271 grams 

 or 18.13 per cent of the total nitrogen. This high result on a 

 low protein diet is in accordance with the findings of Folin as 

 stated above. 



Total phosphates. — The amount of total phosphates was de- 

 termined by means of the uranium acetate method. (18) Phos- 

 phates are present in the urine as monosodium and disodium 

 phosphates and free phosphoric acid. The total amount of phos- 

 phates as phosphoric anhydride (P2O,,) in the urine of Amer- 

 icans is given as from 3.44 to 4.50 grams a day (an average of 

 3.87), and in Europeans, from 2 to 3.5 grams. The relation 

 of phosphate to nitrogen excretion is from 1 to 5 or 6. The 

 average in the Filipino series of 210 determinations was 1.285 

 grams phosphoric anhydride, and the ratio of this to nitrogen 

 is 1 to 5.45. This figure is in comparatively close agreement 

 with Aron's(5) finding for Filipinos, but is smaller than the 

 European ratio, and slightly higher than the American ratio 

 of 1 to 4.1. It is a well-recognized fact that the amount of 

 phosphorus excretion is proportional to the quantity of protein 

 diet. It is still more dependent upon the phosphate absorption. 

 In man from 50 to 60 per cent of the intake is found in the 

 urine, and 30 to 50 per cent in the faeces. For this reason a 

 study of phosphorous excretion in the urine alone affords an 

 unreliable elimination index- 



Total sulphates. — The total oxidized sulphur was determined 

 in the majority of cases by the Rosenheim and Drummond 

 method (19) and in a few cases by Folin's gravimetric method. (20) 

 The sulphates found in urine are derived mostly from the oxi- 

 dation of sulphur of ingested protein molecules, and a relatively 

 small amount is due to the ingested sulphates. The greater 

 part of the sulphur is eliminated in the oxidized form; only a 

 small proportion is excreted in the form of unoxidized or neu- 

 tral sulphur compound. Under normal conditions the output 

 of sulphuric acid is about 2.5 grams daily. About 75 to 95 per 

 cent of this is in the form of oxidized sulphur, and about 90 per 



