394 CHEMISTRY OF THE PROTEIDS CHAP. 



comes heart-muscle, and finally skeletal muscle, according to Bottazzi 

 and Ducceschi, 1 and Vincent and Lewis. 2 



VI. THE NUCLEO-ALBUMINS OR PHOSPHO-GLOBULINS 



The nucleo-albumins .contain phosphorus, and for this reason they 

 were classed at first with the ' nucleo-proteids,' with which they alsc 

 have in common that the complex to which the phosphorus is attached 

 becomes split off during a certain stage of peptic digestion as an 

 insoluble compound, while the main bulk of the albumin -molecule 

 passes into solution. This complex, which is insoluble at first, 

 arid which becomes dissolved later on, Kossel 3 calls paranuclein 

 and Hammarsten 4 pseudo-nuclein. 



The nucleo-albumins differ, however, completely from the nucleo 

 proteids, as neither xanthin- bases, nor pyrimidin- derivatives, noi 

 pentoses occur amongst their dissociation -products. 5 Kossel and 

 Hammarsten, to whom we owe our knowledge regarding the com 

 position of the nucleo-proteids, originally made an attempt to brin 

 the nucleo-albumins and nucleo-proteids closer together by drawing 

 an analogy between the so-called thyminic acid (which is the complex 

 remaining after the xanthin-bases have been split off from nucleic 

 acid) and the pseudo-nuclein or pseudo-nucleic acid. More accurate 

 investigations have shown, however, that the nucleo-albumins and the 

 nucleo-proteids are not at all closely related, 6 and as the nucleo 

 albumins have nothing to do with the cell-nuclei, Cohnheim suggests 

 to discontinue the use of the term ' nucleo-albumin ' and to substitute 

 for it the expression ' phospho-globulin.' 



To this group of bodies belong casein, vitellin, and a numbei 

 of cell-phospho-globulins. Ichthulin is not included here, but classi 

 fied as a phospho-glyco-proteid amongst the proteids, according tc 

 Hammarsten (see p. 405). To the phospho-globulins belong furthei 

 the phyto-vitellins, such as legumin, and perhaps also plant-casein 

 which have been discussed above under No. III. along with the 

 phyto-globulins. 



The phospho-globulins are distinctly acid; they redden litmus 



1 Bottazzi and Ducceschi, Arch. Hal. de Biol. 28. 395 (1897). 



2 Swale Vincent and Thomas Lewis, Journ. of Physiol. 26. 445 (1901). 



3 A. Kossel, Verh. d. Berl. physiol. Ges., Arch. f. Atiat. u. Physiol., Physiol 

 Abteil. 1891, p. 181 ; L. Lilienfeld, ibid. 1892, p. 128. 



4 0. Hammarsten, Zeitschr. f. physiol. Chem. 19. 19 (1893). 



5 A. Kossel, ibid. 1O. 248 (1886). 



6 A. Kossel and A. Neumann, ibid. 22. 74 (1896) ; A. Neumann, Arch. f. Anat 

 und Physiol., Physiol. Abteil. 1898, p. 374 (Verh. d. Berl. physiol. Ges.). 



