346 



EXCRETION. 



Fig. 112. 



CREATIVE, crystallized from hot water. (After 



herbivorous quadrupeds ; but there is little or none to be found in 

 that of birds and reptiles. 



CREATIVE. This is a neutral crystallizable substance, found in 

 the muscles, the blood, and the urine. It is soluble in water, very 



slightly soluble in alcohol, and 

 not at all so in ether. By boil- 

 ing with an alkali, it is either 

 converted into carbonic acid 

 and ammonia, or is decomposed 

 with the production of urea and 

 an artificial nitrogenous crys- 

 tallizable substance, termed sar- 

 cosine. By being heated with 

 strong acids, it loses two equiva- 

 lents of water, and is converted 

 into the substance next to be 

 described, viz., creatinine. 

 Creatine exists in the urine, 



- . , . , 



m the human subject, in the 

 proportion of about 1.25 parts, 



and in the muscles in the proportion of 0.67 parts per thousand. 

 Its quantity in the blood has not been determined. In the muscu- 

 lar tissue it is simply in solution in the interstitial fluid of the parts, 

 so that it may be extracted by simply cutting the muscle into 

 small pieces, treating it with distilled water, and subjecting it to 



pressure. Creatine evidently 



Fi g 113. originates in the muscular tis- 



sue, is absorbed thence by the 

 blood, and is finally discharged 

 with the urine. 



CREATININE. This is also a 

 crystallizable substance. It dif- 

 fers in composition from crea- 

 tine by containing two equiva- 

 lents less of the elements of 

 water. It is more soluble in 

 water and in spirit than crea- 

 tine, and dissolves slightly also 

 in ether. It has a distinctly 



CREATININE, crystallized from hot water. 

 (After Lehmauu.) 



