ix THE PHOSPHO-GLOBULINS 405 



Goat- and horse -caseinogen dissociate when dried into two sub- 

 stances, as does cow-caseinogen, according to Laqueur and Sackur, 

 Horse-milk contains, according to Wroblewski, much opalisin. 



2. Vitellin 



From the yolk of hens' eggs may be prepared a phosphorus- 

 containing albuminous substance, which was investigated by Hoppe- 

 Seyler, 1 and called by him 'vitellin.' According to Zadik 2 it 

 contains 12 per cent nitrogen and T31 per cent phosphorus. Its 

 coagulation-temperature is given by Weyl 3 as 75; it is not salted 

 out by sodium chloride, according to Weyl. Till now vitellin has not 

 been obtained free from lecithin ; Hoppe-Seyler assumed vitellin to be 

 a compound with lecithin, in short, a 'lecith-albumin.' The paranucleic 

 acid derivable from vitellin has been carefully investigated by Bunge, 4 

 who calls it 'hsematogen,' while Levene and Alsberg 5 simply call it 

 paranucleic acid.' Both preparations were, however, not free from 

 albumin, and the analyses differ for this reason greatly from one 

 another. Levene and Alsberg found a phosphorus-content of 9 '88 

 per cent. This substance contains masked iron (see p. 447, under 

 the nucleo-proteids). 



Neuberg 6 has obtained glucosamin from an albumin occurring in 

 the yolk, and also a radical which by oxidation is converted into 

 ^-saccharic acid. That this albumin, which was first prepared by 

 Mayer, 7 is identical with vitellin is probable, judging by the account 

 given of its solubility. If this be so, then vitellin resembles ichthulin 

 even more closely, for the latter also contains a carbohydrate radical. 

 The similarity between vitellin and ichthulin was first pointed out 

 by Hoppe-Seyler. 8 



3. Ichthulin 



Substances closely resembling the vitellin of hens' eggs are also 

 found in the eggs of fish ; they have been known for a long time, and 

 attracted attention because they occur in a crystalline form as the 



1 F. Hoppe-Seyler, Medizin-chem. Untersuchungen, p. 215 (1868) ; J. L. Parke, 

 ibid, p. 209 ; Diakonow, ibid. p. 221 (1868). 



2 H. Zadik, Pfluger's Archiv, 77. 1 (1899). 



3 Th. Weyl, Zeitschr. f. physiol. Chem. I. 72 (1877). 



4 G. Bunge, ibid. 9. 49 (1884). 



5 P. A. Levene and C. Alsberg, ibid. 31. 543 (1900). 



6 C. Neuberg, Ber. d. deutsch. chem. Ges. 34. III. 3963 (1901). 



7 P. Mayer, Deutsch. med. Wochenschr. 1899, p. 95. 



8 M. Gobley, Journ. de Pliarm. et de Chim. 3rd ser. 17. 401 (1850) ; A. 

 Valenciennes and E. Fremy, Compt. rend. 38. 471 (1854) ; F. Hoppe-Seyler, Medizin- 

 chem. Unters. pp. 215, 221 (1868) ; F. N. Schulz, Kristallis. von Eiweiss. Jena, 1901. 



