88 NUCLEIN. 



is doubtless the substance which led to certain erroneous statements as to the 

 production of a true dextrose from chitin 1 . 



Nuclein. C 29 H 49 N 9 P 3 22 (?). 



The nuclei of cells, both animal and vegetable, differ distinctly in 

 chemical composition from the remaining substance of the cells. As 

 a result of this difference it is possible to separate the nuclei approxi- 

 mately by various means from the adjacent cell-substance. The name 

 nuclein is given to the material of which the nuclei or parts of nuclei 

 thus isolated chiefly consist. When however the statements of the 

 various authors who have dealt with nuclein are compared with regard 

 to the reactions, decompositions, and more especially the percentage 

 composition of their preparations, it appears probable that no definite 

 substance exists to which the one name nuclein may be fitly applied. 

 It may be that the discrepancies are due to the existence of several 

 kinds of nuclein 2 ; but this is as yet scarcely proved, and it is on the 

 whole more probable that the different results of the various authors 

 must be attributed to the impurity of the substance on which they 

 operated 3 . In accordance with this view it is to be observed that the 

 percentage of phosphorus obtained in even the most reliable analyses 

 is stated to vary from 2-3 to 9-6 p.c. 



After the above precautionary remarks we may now give an 

 account of the preparation and properties of the so-called nuclein. 

 When a mass of cells such as pus 4 , yeast 5 , nucleated red blood- 

 corpuscles 6 , salmon-milt 7 or egg-yolk 8 is extracted with water and 

 dilute (*5 p.c.) hydrochloric acid, the cells are largely broken up and 

 dissolved', and the nuclei separated from them. A further purification 

 is obtained by treatment with alcohol and ether and final digestion 

 with pepsin in acid solution, which does not affect the substance of the 

 nuclei 9 . The final residue thus obtained is washed with dilute acid, 



1 Berthelot, Compt. Rend. T. XLVII. (1858) p. 227. Journ. de la Physiol. T. n. p. 

 577. 



2 Hoppe-Seyler, Hdbch. d. physiol.-path. chem. Anal. (5 Auf.), 1883, S. 303. 

 Physiol. Chem. S. 85. 



3 Worm-Miiller, Pfliiger's Arch. Bd. vm. (1874), S. 190. Bunge, Physiol.-pathol. 

 Chem. (Transl. by Wooldridge, 1890), p. 89. 



4 Miescher, Hoppe-Seyler 's Med.-chem. Untersuch. Hft. rv. (1871), S. 452. Hoppe- 

 Seyler, Ibid. S. 486. 



5 Hoppe-Seyler, Ibid. S. 500. Kossel, Zt. physiol. Chem. Bd. in. (1879), S. 284; 

 iv. (1880), S. 290; vn. (1883), S. 7. Unters. iib. 'd. Nucleine u. ihre Spaltungsprod. 

 Strassb. 1881. Loew, Pfliiger's Arch. Bd. xxn. (1880), S. 62. 



6 Brunton, Jl. Anat. and Physiol. 2 Ser. Vol. m. 1869, p. 91. Pl<5sz, Hoppe- 

 Seyler's Med.-chem. Unters. Hft. iv. (1871), S. 461. 



7 Miescher, Verhand. d. Natforsch. Gesell. Basel, Bd. vi. (1874), S. 138. 



8 Miescher, Hoppe-Seyler's Med.-chem. Unters. Hft. iv. (1871), S. 502. Worm- 

 Miiller, loc. cit. 



9 It also resists the action of trypsin. Bdkay, Zt. /. physiol. Chem. Bd. i. (1877), 

 S. 157. 



