REVIEW OF THE LITERATURE. 7 



Liebig 1 named the part of the gluten that was insoluble in alcohol ' ' plant- 

 fibrin," on account of its supposed resemblance to blood-fibrin. The sub- 

 stance soluble in alcohol he called ' ' plant-gelatin ' ' and considered it to be 

 a compound of a protein with an organic acid. In the aqueous extract of 

 the flour he recognized the presence of albumin. 



Scherer 2 prepared plant-fibrin by dissolving gluten in dilute alkali, filter- 

 ing, neutralizing with acetic acid, and extracting the precipitate with hot 

 alcohol and then with ether. 



Bonchardat 3 considered that wheat gluten contained a protein soluble in 

 extremely dilute acids, which he named " albuminose." 



Dumas & Cahours 4 found four protein substances in wheat flour, namely, 

 plant-fibrin, which remained after extracting gluten with alcohol ; a sub- 

 stance which they considered similar to casein,, which was deposited by 

 cooling the alcoholic extract ; glutin, which was obtained by concentrating 

 and cooling the alcoholic extract, and albumin, which was present in the 

 aqueous washings of the gluten and was coagulated by boiling. The plant- 

 fibrin they considered to be identical with blood-fibrin, as both had the same 

 ultimate composition, and the albumin to be identical with egg-albumin for 

 the same reason. 



Mulder 5 considered the plant-gelatin, obtained by extracting gluten with 

 alcohol, to be a compound of sulphur with " protein," which contained the 

 same proportion of sulphur as blood-albumin. 



Von Bibra 6 recognized three proteins in gluten plant- fibrin, which 

 formed 70.8 per cent; plant-gelatin, 16.2 per cent; and plant-casein, 7.1 

 per cent. In the water used for washing out the gluten he found 1.34 per 

 cent of albumin. 



Giinsberg 7 considered that Taddei's view that there were only two pro- 

 teins in wheat gluten was correct. By boiling wheat gluten with water he 

 obtained five preparations which separated on cooling and had the same 

 ultimate composition as has been established for gliadin. By treating 

 gliadin in the same way he obtained a body of the same composition. The 

 substance which Giinsberg thus obtained was unquestionably gliadin, which 

 is sparingly soluble in hot water, and he appears to have been the first to 

 obtain correct analyses of this protein. 



1 lyiebig, Annalen der Chemie und Pharmacia, 1841, xxxix, p. 129. 



2 Scherer, Annalen der Chemie und Pharmacie, 1841, xi,, p. 7. 



3 Bonchardat, ibid., 1842, xui, p. 124. 



1 Dumas & Cahours, Journal fur praktische Chemie, 1843, xxviu, p. 398. 



5 Mulder, Annalen der Chemie und Pharmacie, 1844, ui, p. 419. 



6 Von Bibra, Die Getreidearten und das Brod, Nuremberg, 1860. 



7 Gunsberg, Journal fur praktische Chemie, 1862, i<xxxv, p. 213. 



