92 CHEMISTRY OF THE PROTEIDS CHAP. 



By mixing chemically pure tryptophane or indoj-amino-propionic 

 acid with eight to ten times its weight of caustic potash, adding some 

 water and heating for only a short time after water has ceased to come 

 off, allowing to cool, adding some more water, and heating again and 

 repeating this addition of water three or four times, Hopkins and 

 Cole 1 obtained in the distillate 65 per cent of what would be the 

 theoretical yield of skatol. The distillate also contained an abundance 

 of ammonia, and gave a slight nitroso-indol reaction. In the non-vola- 

 tile residue from the potash-fusion abundant oxalic acid could always be 

 detected, and at times it was possible to show the presence of glyoxylic 

 acid. These two products, along with ammonia, are derived from the 

 side-chain of the indol-amino-propionic acid under the combined hydro- 

 lytic and oxidative influence of potash. 



Skatol, on being fused with potash, yields /3-indol-carboxylic acid, 

 according to Ciamician and Magnanini, 2 and Ciamician and Zatti. 3 



Dry distillation of the most diverse albumins also gives rise, 

 according to Rubner, to sulphuretted hydrogen, H 2 S ; ethyl-mercap- 

 tane, C 2 H 5 . SH ; and methyl-mercaptanes, CH 3 . SH. 



(b) The Disintegration of Albumins by Superheated Steam 



At first, again, amino-acids are liberated, of which Lubavin 4 found 

 leucin and tyrosin, while Steudel 5 demonstrated aspartic acid. Later 

 on, according to Steudel, 5 all hexone bases disappear completely. (See 

 also p. 202.) 



(c) The Disintegration by means of Oxidising Media 



The primary changes produced by oxidising media in albumins 

 are fully discussed on pp. 237 to 249. 



1. Potassium Permanganate in Combination with Sulphuric or Chromic 

 Acid. This method was employed under the direction of Liebig by 

 Guckelberger, 6 who investigated egg-white, fibrin, casein, and gelatine, 

 but only the volatile products were isolated. He obtained formic, 

 acetic, propionic, butyric, valerianic, and caproic acids ; benzoic acid, 

 an aldehyde ; ammonia, oil of bitter almonds, different nitrites ; finally, 

 a 'heavy oil smelling of cinnamon.' According to E. Fischer, 7 phenyl- 



1 Hopkins and Cole, Journ. of Physiol. 29. 463 (1903). 



2 Ciamician and Magnanini, Ber. d. deutsch. chem. Gesellsch. 21. 673 (1888). 



3 Ciamician and Zatti, ibid. 21. 1933 (1888). 



4 N. Lubavin, Hoppe-Seyler's mediz.-chem. Untersuch. p. 463 (1871). 



5 H. Steudel, Zeitschr. f. physiol. Chem. 35. 540 (1902). 



6 Guckelberger, Liebig's Ann. 64. 39 (1848). 



7 E. Fischer, Zeitschr. f. physiol. Chem. 33. 151 (1901). 



