336 THE MUCOID NUCLEO-ALBUMIN OF BILE. [BOOK II. 



albuminous body and a carbohydrate 1 . Landwehr, experimenting on 

 the so-called rnucin of bile, observed that when boiled with dilute 

 acids it did not, like the mucin of the salivary glands or the mucin 

 of Helix pomatia, yield a substance which exerts a reducing action, 

 and he advanced the hypothesis that in all probability it consisted of 

 a mixture of globulins with bile acids 2 , an hypothesis which has 

 however been disproved. 



Fundamental The researches of Hammarsten 4 and others have 

 distinction be- made us acquainted with a class of albuminous bodies 

 tween 'the widely distributed throughout the protoplasmic struc- 

 ^h^nucieo 1 tures of animal bodies and typically represented by 

 albumins 3 .' casein, bodies which have been associated together as 

 a family of the albuminous substances under the name 

 of the nucleo-albumins. Just as it is characteristic of the mucins to 

 split up, when subjected to certain hydrolytic agencies, into a proteid 

 and a carbohydrate moiety, so is it a characteristic of a nucleo- 

 albumin to split up, under the same conditions, into a proteid and 

 into a phosphorus-containing nuclein, for all the nucleo-albumins 

 contain phosphoruses an essential element of their molecule.. 



The re- Working under the direction of Hammarsten, 



of Paijkull 5 has separated the body which confers upon 

 bile its viscidity and has conclusively proved that it 

 belongs to the nucleo-albumins, resembling in its characters the 

 mucin-like nucleo-albumin which Hammarsten discovered to be a 

 constituent of the synovial fluid. 



Methods of The methods which were formerly employed to 



separation of precipitate, what was termed, the mucin of bile are 

 the mucoid not available for the separation of the body. Acids 

 precipitate not only the nucleo-albumin but also bile 

 acids, and the latter cannot be separated by alcohol 

 from the former without rendering the nucleo-albumin insoluble. 



1 H. A. Landwehr, ' Untersuchungen iiber das Mucin von Helix pomatia und ein 

 neues Kohlenhydrat (Achrooglycogen) in der Weinbergschnecke,' Zeitschr. f. phys. 

 Chemie, Vol. vi. (1882), pp. 74 77; 'Ein neues Kohlehydrat (thierisches Gummi) im 

 menschlichen Korper,' ibid. Vol. vm. (1883 4), pp. 122 128. 



a H. A. Landwehr, ' Ueber Mucin, Metalbumin und Paralbumin,' Zeitschr. f. 

 phys. Chemie, Vol. vm. (18834), pp. 114121, see p. 117. 



3 So far as the Author has been able to discover Hammarsten first suggested the 

 propriety of recognising a group of nucleo-albumins, and first introduced this term, 

 m the following sentence: " Zu den gewohnlichen, kunstlich darzustellenden Alkali- 

 oder Kalk-albuminaten kann das Casein keineswegs gerechnet werden ; und wenn man 

 es nicht zu einer besonderen Gruppe von Stoffen, den Nucleoalbuminen rechnen will 

 was wohl das Richtigste sein wurde muss wohl das Casein mit dem grossten Rechte 

 einen Platz unter den nativen Albuminaten, d. h. den Globulinen, finden." Olof 

 Hammarsten, ' Zur Kenntniss des Caseins und der Wirkung des Labfermentes.' Upsala, 

 1877, p- 75 ; consult p. 45. 



4 0. Hammarsten, 'Studien iiber Mucin und mucin-ahnliche Substanzen,' Pfliiger's 

 Archiv, Vol. xxxvi. p. 373. 



5 L. Paijkull, 'Ueber die Schleimsubstanz der Galle,' Zeitschrift fur phys. Chemie, 

 Bd. xn. (1887), p. 196. 



