THE DECOMPOSITION PRODUCTS OP PROTEIDS. 67 



quantities, according to the degree to which the hydration 

 had been carried out. If this had been thorough the final 

 bodies, viz., the leucines and leuceines, were found, but if it 

 had only been partial large quantities of glucoproteins were 

 obtained. He also found evidence of combinations of these 

 with leucines or leuceines to form still more complex bodies. 

 He therefore concludes that the albumin molecule under 

 the action of barium hydrate loses ammonia, carbonic an- 

 hydride, acetic and oxalic acid, and becoming hydrated 

 forms first glucoproteins, mainly C 9 H l8 N 2 4 or more pro- 

 bably a multiple of this, and on further action these become 

 converted into bodies of the leucine and leuceine type. 



He has further extended his observations to other pro- 

 teids and shown that they give almost identical results. 



Under the same treatment gelatine, icthyocoll and ossein 

 were found to yield the same bodies, with the addition of 

 amido-acetic acid (glycocine) in very large quantities (20-25 

 per cent.). 



2. Acids. Prolonged heating of proteids with dilute 

 acids was found by Neumeister 1 to result in hydration and 

 the production of proteoses and peptones. I have observed 

 the production of the same bodies by the action of strong- 

 acids acting for several days at the temperature of the room. 

 The prolonged boiling with a strong solution of sulphuric 

 or hydrochloric acids yielded ammonium salts, leucine, 

 tyrosine, aspartic and glutaminic acid. This method had 

 the great disadvantage that many strongly coloured bodies 

 appeared, and to avoid this Hlasiwetz and Habermann 2 in- 

 troduced the important modification of heating with strong 

 hydrochloric acid and stannous chloride, by which pale 

 yellow solutions were obtained which showed no trace of 

 charring. At the end of the process most of the stannous 

 chloride was found converted into stannic chloride, showing 

 that a certain amount of reduction had occurred. Casein 

 was the proteid at first employed by them in their re- 

 searches, and from the liquid so obtained they were able to 

 isolate : — 



1 Zeitschr. fiir Biologie, vol. 23, p. 381. 



2 Liebig's Annakn der Chemie, vol. 169, p. 150, 1873. 



