46 



Fig. 10. Aluminum Tubes 



Sedimentation 

 Tube. 



the average of a great number of control tests with the burette it 

 has been found that Vio cc of the precipitate, in the case of the 

 phosphates, represents 0.13 gram of P.Og in 1000 cc. of urine. 

 If albumin is present, remove it by adding a little acetic 

 acid and applying heat. Filter and test the filtrate for the inor- 

 ganic constituents. 



With the horse urine care must be exercised in adding the 

 reagents. The large amount of carbonates present cause con- 

 siderable effervescence, from the liberation of the CO,, and some 

 of the urine is likely to flow over the tube. Add a little of the 

 reagent and when the effervescence has ceased add a little more 

 until the required amount has been used. j 



Phosphates. Fill the graduated tube to the 10 cc, 

 mark with the urine to be tested. Add 1 cc. of glacial 

 acetic acid and 4 cc. of 5% uranium nitrate solution to 

 reach the 15 cc. mark. Invert the tube several times and 

 revolve in the centrifuge for three minutes. If, after re- 

 volving three minutes at 1000 revolutions per minute, the 

 precipitate comes up to the eighth 0.1 cc. line of the tube 

 (0.8 cc.) multiply 0.13 by 8 for the product, which is 1.04 

 grams of PoOg in 1000 cc. If the total amount of urine for 

 the 24 hours is 1400 cc, the amount of PoOg present in this 

 quantity can easily be calculated by the following propor- 

 tion : 1.04 gm. P.O., : 1000 cc. : : X : 1400. In which the 

 value of X is found to be 1.456 grams of PoO., in 24 hours. 

 Make the same determination with the urine of the horse. 



