142 DIGESTION. 



Proteoses. The following reactions, which may be regarded 

 as the best marked class distinctions, are all that can be 

 attempted here. Fluid (A) which has stood after neutralisa- 

 tion should be filtered through double paper, the filtrate 

 will be free of acid proteid and nearly clear. It contains 

 proteoses and pepton 1 . 



Primary proteoses (proto- and hetero-proteose) 



1. Saturate a tubeful with NaCl crystals, a pp separates, 

 consisting principally of primary proteoses much of this pp 

 is carried to the top with the froth filter. 



Secondary proteoses (deutero-proteose). 



2. To the filtrate from (1) which is quite clear, add a few 

 drops of acetic acid, a further pp will form, consisting 

 mainly of deutero-proteose, but containing a little proto- 

 proteose as well. 



NOTE. The primary proteoses are formed first and the 

 secondary proteoses next. The relationship which these sub- 

 stances are supposed to bear to the parallel chains of cleavage 

 products of the proteid molecule, known as the hemi- and 

 anti-groups, may in brief be expressed as follows : Profco- 

 proteose is stated to be the first link in the hemi- and 

 hetero-proteose the corresponding link in the anti-chain, 

 whilst the next link in each is a deutero-proteose. 



Recognition of free Hydrochloric and Lactic acids. 

 Perform the following reactions with watery solutions of the acids, 

 by adding them drop by drop to \ tubeful of the reagent: 



HC1 0-1 P- C - C 8 H 6 O 8 0-01 p - c - 



1. Congo red (Hosslin) ... Blue 



2. Carbol-iron (Uffelmann) Pale yellow. 

 Carbol-iron test. To 10 cc of a 4 1XC - solution of carbolic acid 



add 20 cc distilled water and 1 Liquor Ferri perchloridi B.P. 



i What is the definition of a pepton? 



