GREATINE AND CREATININE. 311 



it is 47 per cent. In the albuminoid group the carbon amounts 

 to 52 or 53 per cent ; in urea the carbon is no more than 20 

 per cent. The hydrogen is very much the same in both ; but 

 the oxygen in the albuminoid group is about 22 per cent, 

 while in urea it is 27 per cent. 



Creatine consists of oxygen, hydrogen, carbon, and nitrogen. 

 It has neither acid nor basic properties. It is very soluble in 

 hot water, and cold water retains a minute proportion of it in 

 solution. By the action of strong acids it is resolved into crea- 

 tinine. Creatine is found in minute quantity in the muscular 

 flesh of the common domestic quadrupeds, and also in that of 

 birds and fishes. Creatine and creatinine are found in minute 

 quantity, along with urea, in the urine. 



Uric Acid. Uric acid consists of oxygen, hydrogen, carbon, 

 and nitrogen. Both the nitrogen and the carbon are in con- 

 siderable proportion. Nitrogen is present to the extent of 32 

 per cent, while the carbon amounts to 37 per cent. Uric acid 

 is secreted not only by mammals and birds, but also by serpents 

 and many insects. Guano consists chiefly of uric acid combined 

 with ammonia, altered by the greater or less exposure to the 

 elements to which it may have been subjected. 



Hippuric Acid. The urine of the horse yields hippuric acid 

 if the animal be kept at rest ; but if he be employed actively 

 at work the greater part of the hippuric acid disappears, and 

 benzoic acid is found in its stead. This acid is readily obtained 

 from the urine of the cow. The acid consists of oxygen, hydro- 

 gen, carbon, and nitrogen, but contains no more than 8 per 

 cent of nitrogen. 



Saccharine or Amylaceous Group of Proximate Principles. 



The types of the saccharine or amylaceous group of proxi- 

 mate principles in organic nature are chiefly from the veget- 



