IMMEDIATE PRINCIPLES OF THE TISSUES. 



Urate of ammonia. 



Uric acid also exists in the blood, the 

 precise amount being not yet determined. 

 It is, however, always increased in it in 

 acute gout, and often in Bright's disease. 

 It is not increased in acute rheumatism. 

 From .004 to .0175 per cent, has been 

 found in the blood of gouty patients. 

 ( Garrod.) 



Origin. Though uric acid is doubtless 

 a result of waste of the tissues, it is not 

 certain from what substance nor in what 



locality it is first formed. It appears to stand "one degree higher 

 in the scale of the descending metamorphosis of matter than urea" 

 (Lehmann) i.e. it is converted into urea (and oxalic acid) by a 

 partial oxidation. Hence, when aeration, and consequently oxy- 

 genation, is imperfect, more uric acid and oxalate of lime, and less 

 urea, appear in the urine. 



3. Hippuric Acid. (C 18 H 8 N0 5 .HO.) 



Hippuric (or uro-benzoic) acid is present in the urine during the 



use of a vegetable or a mixed 

 diet. It occurs in large quan- 

 tity in acid febrile urine, what- 

 ever the variety of febrile ex- 

 citement, and in diabetic urine. 

 (Fig. 25.) 



The hippuric has no ascer- 

 tained relationship to the uric 

 acid, nor is any thing certainly 

 known of its origin. It is 

 doubtless formed from the effete 

 tissues, and has no special use in 

 the organism. The hippurate 

 of lime, soda, and potassa are 



Crystals of hippuric acid from human urine. also immediate principles. 



4. Oxalate of Lime. (CaO.C 2 3 .) 



This salt is frequently present in very small amount in normal 

 urine ; much increased, it indicates a pathological condition. The 

 forms of its crystals are indicated by Figs. 26 to 29. 



Fig. 25. 



