252 GLUTAMIC ACID. [BOOK II. 



Physical and Chemical Properties. 



Aspartic acid crystallises in small white plates. 



_ . ..... It is soluble with difficulty in cold water and 



Solubility. , , , . , , , J 



insoluble in alcohol. 



Rotatory Its aqueous solution is laevo-rotatory ; its strongly 



power. acid solutions are dextro-rotatory and its alkaline solu- 

 tions are Isevo-rotatory (Pasteur, Ritthausen) 1 . A nitric acid solution 

 of aspartic acid has a specific rotation (a)j) = 4- 25-16 (Landolt). In- 

 active aspartic acid is obtained when the normal acid is heated to 

 170 180 with hydrochloric acid (A. Michael and J. Wing) 2 . 



Qlutamic acid C 5 H 9 N0 4 . 

 (Amido-pyrotartaric acid C S H 5 (NH 9 )(COOH) 2 .) 



Occurrence. Glutamic acid, as has been already said, was found 



by Ritthausen and Kreusler amongst the products of the decom- 

 position of vegetable albuminous substances. Kreusler 3 having 

 failed to obtain it by the decomposition of proteids of animal origin, 

 advanced the view that it was one of the products which distinguished 

 them from the kindred bodies of the vegetable kingdom. Hlasiwetz 

 arid Habermann 4 , however, shewed, first of all in the case of casein 

 and then in that of other animal proteids, that when decomposed by 

 means of stannous chloride and hydrochloric acid, glutamic acid is 

 formed. From casein they obtained by their method 29 per cent, of 

 glutamic acid. 



By the decomposition of " reticulin," the new phosphorus-con- 

 taining proteid, which he has found to be distinctive of adenoid 

 tissue, Siegfried has obtained a small quantity of glutamic acid 5 . 



Method of The reader is referred for detailed information as to 



S ! Pa i ti0 S and tne methods of separating glutamic acid from the 

 identification. . , . , r , . , 9 & 



other amido-acids which always accompany it, to tne 



already quoted memoirs of Hlasiwetz and Habermann, Ritthausen, 

 and Siegfried. Either the sparingly soluble compound, which, like 

 the other amido-acids, glutamic acid forms with copper must be 

 separated, purified, and decomposed, or advantage may be taken of 

 the sparing solubility of the hydrochloric acid compounds of glutamic 

 acid in strong HC1. With this object, the concentrated mother 



1 Landolt, 'Das Optische Drehungsvermogen Organischen Substanzen.' Braun- 

 schweig, 1879. See p. 222. 



2 A. Michael and J. Wing, Berichte d. deutsch. chem. Gesellschaft, Vol. xvn. 

 p. 2984. 



3 Kreusler, Journ. f. prakt. Chemie, Vol. cvn. p. 240. 



4 Hlasiwetz und Habermann, ' Ueber die Proteinstoffe II.' Ann. d. Chemie, &c. 

 Vol. CLXIX. p. 150. 



6 Dr Max Siegfried, ' Ueber die Chemischen Eigenschaften des Keticulirten Gewebes,' 

 Habilitationschrift, Leipzig, Dec. 1892. 



