742 APPENDIX. 



Amido-Acids. 



Glycin, Glycocol, Glyco- ) n TT ^ n / P TT /NH 2 \ 

 cm, or Amido-aceticacid \ Q H * N0 = i H <00 OH> 



This substance occurs in the body in combination as in the biliary 

 acids, but is never free. Glycocholic acid, when treated with weak 

 acids, with alkalies, or with baryta water, splits up into cholic acid and 

 glycin, or amido-acetic acid. Thus: 26 H 43 N0 6 4- H 2 = C a6 H 40 5 

 + C 2 H 5 N0 2 . Glycocholic acid + water = cholic acid + glycin, 

 and under similar circumstances Taurocholic acid splits up into cholic 

 acid and taurin: C 26 H 45 3 NSO a + H 2 = C 26 H 40 5 + C 2 H 7 NS0 3 , 

 or amido-isethionic. Taurocholic acid 4- water = cholic acid and 

 taurin. Glycin occurs also in hippuric acid. It can be prepared from 

 gelatin by the action of acids or alkalies; it can also be obtained from 

 hippuric acid. 



Sarcosin or Methyl I n TT TSTO f- PH / NH CH * ^ It is 

 Glycin, fi*rv.Vf= H \CO OH J' 



stituent of kreatin, and also of caffeine, but has never been found free in 

 the human body. It may be obtained from these bodies by boiling with 

 baryta water. 



" [ . H N0 .( = CH..OH.CH 1 CH,.CH(NH 1 ) 



CO OH occurs normally in many of the organs of the body and is a pro- 

 duct of the pancreatic digestion of proteids. It is present in the urine 

 in certain diseases of the liver in which there is loss of substance, espe- 

 cially in acute yellow atrophy. It occurs in circular oily discs or 

 crystallizes in plates, and can be prepared either by boiling horn shavings, 

 or any of the gelatins with sulphuric acid, or out of the products of 

 pancreatic digestion. 



Amido-sulplionic Acids. 



Taurin, or Amido- ) n T r ATQ^ I n TT /SO,H\ 

 isethionic Acid, [ > H ' NS0 4 = C H <NH J " 



of the bile acid, taurochloric acid, and is found also in traces in the 

 muscles and lungs. It has been prepared synthetically from isethionic 

 acid. It is a crystalline substance, very stable. 



Benzoyl Amido-acids. 



} C,H,N0 3 =(C 6 H 5 CONH CH,COOH), a normal 



constituent of human urine, the quantity excreted being increased by a 

 vegetable diet, and therefore it is present in greater amount in the urine 

 of herbivora. It may be decomposed by acids into glycin and benzoic 

 acid. It crystallizes in semi-transparent rhombic prisms, almost insolu- 

 ble in cold water, soluble in boiling water. (See also p. 368.) 



