ii SECONDARY DISSOCIATION-PRODUCTS 97 



23'8 grammes Aspartic acid (and perhaps glutaminic acid). 

 22-6 Leucin. 

 1*5 ,, Bromanil. 



Further, carbonic acid, the amount of which was not determined. 

 Other albumins yielded the same products, but in different proportions. 



(h) Disintegration by means of Sulphur 



On mixing egg-white with flowers of sulphur or with precipitated 

 sulphur, there is soon liberated sulphuretted hydrogen, which blackens 

 lead-acetate-paper. After various explanations had been offered which 

 were purely speculative, Nasse and Rosing x recognised that the process 

 was one of oxidation. They assumed that in egg-albumin a labile, i.e. 

 loosely attached hydrogen-atom, was replaced by a hydroxyl-radical of 

 water, and that the H derived from the albumin, along with the re- 

 maining H of the water-molecule, united with sulphur to form H 2 S. 

 This view is supported by the fact that benzaldehyde, acetaldehyde or 

 cenanthol by autoxidation give rise to H 2 S in the presence of sulphur 

 and water. 



According to Engler, 2 however, autoxidation takes place in a 

 different manner. An oxygen-molecule takes the place of the labile 

 hydrogen-atom in the autoxidator, giving rise thereby to a peroxide. 

 The hydrogen-atoms which are set free are then supposed to unite 

 with sulphur to form H 2 S. 



Against the view of Nasse may be urged, that aldehyde-groups 

 have not yet been shown to occur in albumins ; and against Engler, that 

 egg-white is unable to oxidise an acceptor, i.e. a substance which under 

 otherwise equal conditions is not directly oxidisable, such substances 

 being, e.g., arsenious acid and indigo-sulphuric acid. 



Nasse and Rosing were right in assuming that an oxidation-process 

 is set up by the action of sulphur on egg-white, as traces of other 

 oxidising media will prevent the sulphur from being changed into 

 H 2 S, according to Heifter, 3 who believes that the sulphur simply 

 takes away the H from the albumin-molecule, as happens also when 

 diphenyl-me thane and sulphur are heated together, there being formed 

 tetraphenyl-ethylene and H 2 S (Ziegler 4 ). 



1 Rosing, Untersuchungen iiber die Oxydation von Eiweiss in Gegenwart von Schwefel. 

 Dissertation (under 0. Nasse), Rostock, 1891. 



2 Engler, Ber. d. deutsch. chem. Ges. 33. 1097 (1900). 



3 A. Heffter and Max Hausmann, Hofmeisters Beitrage, 5. 213 (1904). Here com- 

 plete literature. 



4 Ziegler, Ber. d. deutsch. chem. Ges. 21. 779 (1888). 



H 



