1242 



GLYCINE. 



alcohol. The crystals separate out from this solution on con- 

 centration, and may be purified by recrystallization. 



The crystals are insoluble in alcohol, ether and chloroform, 

 slightly soluble in cold and readily so in hot water. Dilute 

 acids and alkalis also dissolve them readily. 



It has been stated that the crystals are in reality a com- 

 pound of phosphoric acid with a nitrogenous base to which the 

 name spermine has been given, and the formula C 2 HgN (?) has 

 been assigned. This base is obtained by the addition to the 

 crystals of baryta-water, which forms a phosphate of barium and 

 liberates the base. It is soluble in water and alcohol, yielding 

 strongly alkaline solutions ; it may be reconverted into Char- 

 cot's crystals by the action of phosphoric acid. This base was 

 at one time regarded as closely related to, if not identical with 

 ethylinimine, C 2 H 4 . NH. It has however been recently shewn 

 that the two substances are not identical, and it has further 

 been stated that the composition of spermine is most probably 

 represented by the formula C 10 H 26 N 4 . 



AMIDES AND AMIDO-ACIDS. THEIR DERIVA- 

 TIVES AND ALLIES. 



AMIDO-ACIDS OF THE ACETIC SERIES. 



1. Amido-formic acid. 



NH 2 .COOH. 



This substance is identical with carbamic acid, one of the 

 amido-derivatives of carbonic acid, the first acid of the oxalic 

 acid series. It will be described under the oxalic group. 



2. Glycine. C 2 H 5 NO 2 . [CH 2 (NH 2 ) . COOH]. (Amido- 

 acetic acid.) (Also called Glycocoll and Glycocine.) 



Does not occur in the free state in the animal body, but 

 enters into the composition of several important substances, 

 more especially hippuric and glycocholic acids. It is also a 

 product of the action of hydriodic acid on uric acid, and of 

 boiling acids and caustic alkalis on gelatin : hence the name 

 glycocoll or gelatin-sugar, since it possesses a sweet taste. It 

 crystallizes in large, colourless, hard rhombohedra, or four- 

 sided prisms, which are easily soluble in water (1 in 4-3), 

 insoluble in cold, slightly soluble in hot alcohol, insoluble 

 in ether. 



Its solutions possess an acid reaction but a sweet taste. 

 Glycine has also the characteristic property of uniting with 

 both acids and bases to form crystallizable compounds, as also 

 with salts. In this it exhibits its amidic nature, which is fur- 



