ii SECONDARY DISSOCIATION-PRODUCTS 93 



alanin gives rise to phenyl-acetaldehyde on being treated with sulphuric 

 acid and bichromate. 



2. Potassium Permanganate in Alkaline Solutions. The products 

 formed at first, still retain their albuminous character, and are discussed 

 in Chapter Y. Subsequently, according to Bernert, 1 are formed acetic, 

 propionic, butyric, and valerianic acids ; lysin, histidin, pyrrol, and 

 ammonia. Kutscher 2 has shown arginin to give rise at first to 

 guanidin-butyric acid and then to guanidin and succinic acid, when it 

 is treated with barium permanganate. Lessen 3 has obtained guanidin 

 also directly from albumin. 



3. Calcium Permanganate in Soiling Solutions. Zickgraf 4 has em- 

 ployed boiling solutions of calcium permanganate for oxidising gelatine, 

 because the calcium oxide which is set free is at once rendered inert 

 through the carbonic acid and the oxalic acid resulting from the oxida- 

 tion of the gelatine, and the oxidation taking place in a boiling solution 

 results in a rapid and complete dissociation of the gelatine-molecule 

 and prevents the formation of partly oxidised substances such as 

 oxy-protsulphonic acid. 



Kutscher and Schenk, 5 by oxidising gelatine with calcium per- 

 manganate, obtained large amounts of oxaminic acid, which is a 

 derivative of glycocoll. The oxaluria which results from feeding with 

 gelatine (Lommel) 6 is readily explained by assuming that the glycocoll 

 of the gelatine is converted in the body into oxamin, and that the 

 latter then splits up into ammonia and oxalic acid. 



4. Hydrogen Peroxide in Acid Solution. Neuberg and Blumenthal 7 

 prepared from gelatine, and Orgler 8 from crystallised egg-albumin, the 

 two substances acetone and isovaleric aldehyde. The latter is derived 

 from leucin, while the acetone may be derived either from leucin or 

 from a hitherto not yet isolated amino-isobutyric acid. 



The action of nitric acid is discussed below. 



To Neumann's excellent method for converting albumin into ash 

 by heating albuminous matter with a mixture of equal volumes of 

 concentrated nitric and sulphuric acids special attention is drawn. 9 



1 R Bernert, Zeitschr. f. physiol. Chem. 26. 272 (1898). 



2 E. Benech and F. Kutscher, ibid. 32. 278 (1901) ; F. Kutscher, ibid. 32. 413 

 (1901). 



W. Lessen, Liebig's Ann. 201. 369 (1880). 

 G. Zickgraf, Zeitschr. f. physiol. Chem. 41. 259 (1904). 

 Fr. Kutscher and Martin Schenk, ibid. 43. 337 (1904). 

 Lommel, Deut. Arch.f. Tdin. Med. 1899. 



C. Neuberg and F. Blumenthal, Hofmeisters Beitr. 2. 238 (1902) ; Deutsche mediz. 

 Wochenschrift, 1901, p. 6. 



8 A. Orgler, Hofmeisters Beitr. 1. 583 (1902). 



9 A. Neumann, Zeitschr. f. physiol. Chern. 37. 115 (1902), and 43. 32 (1904). 



