218 A Manual <>f Veterinary Physiology. 



even this is liable to fallacy from concentration or other- 

 wise of the urine, or from the administration of chlorides 

 to the patient. 



Lime is precipitated by the addition of ammonium oxalate. 

 The fluid should stand some hours to allow the white pre- 

 cipitate to settle. A considerable quantity exists in the 

 urine of herbivora in combination with oxalic and carbonic 

 acids (Figs. 17 and 18). 



Magnesium. — To the fluid from which the lime has been 

 removed by filtration add phosphate of soda and ammonia ; 

 allow to stand some hours ; magnesium settles. Very large 

 crystals may be produced by this process (Fig. 19). 



Sulphuric Acid. — A white precipitate, formed on the addi- 

 tion of barium chloride, insoluble in nitric acid. Before 



Fig. l!». — Crystals <»f Triple Phosphate (Funke). 



adding the barium the fluid should be acidulated with 

 hydrochloric acid ; but the latter must be pure and free 

 from sulphuric acid. 



Phosphoric Acid. — Found only in small quantities in 

 healthy, but largely in acid urine. Phosphates produce a 

 turbidity on heating the urine, removed by the addition of 

 a drop of nitric acid. They produce a precipitate with 

 silver nitrate, soluble in nitric acid. 



Soda and Potash cannot be roughly determined, as they 



