68 CHEMICAL CONSTITUENTS OF BODY AND FOOD. 



able from the nuclei and protoplasm of cells. They appear to be the 

 most abundant of the proteid materials obtainable from cells. Nucleo- 

 histon is the name of one of these separated from the thymus by Kossel 

 and Lilienfeld. 1 The latter gives its percentage composition as 

 C, 4846; H, 7 ; N, 16-86; P, 3-025; S/0'7; 0, 23'95. The high 

 percentage of phosphorus given here has never been obtained by me, 

 from the numerous nucleo-proteids I have prepared and examined from 

 the thymus and other organs. Details of these will be given under the 

 heads of the various organs in question. In my own analyses, the 

 amount of phosphorus rarely has exceeded 1 per cent. 



Nucleo-liiston appears to be identical with the tissue fibrinogen of 

 Wooldridge, but this included a variable amount of lecithin. Other 

 forms of the same substance have bsen called cytoglobin and preglobin by 

 A. Schmidt. 2 Wooldridge prepared his tissue nbrinogens from cellular 

 structures, such as thymus and testis. The gland is finely minced and 

 extracted with water for twenty-four hours. Weak acetic acid is then added 

 to the decanted extract, and after some hours the precipitated nucleo-proteid 

 falls to the bottom of the vessel. This is the method used by Lilienfeld in 

 the manufacture of nucleo-histon. Another method, which I have largely 

 used, is to grind up the finely minced organ with about an equal volume of 

 sodium chloride in a mortar. The resulting viscous mass (originally called 

 hyaline substance by Eovida) is poured into excess of distilled water. The 

 nucleo-proteid rises in strings to the surface of the water, where it may be 

 skimmed off. 



Prepared by either method, the nucleo-proteid may be dissolved in 1 per 

 cent, sodium carbonate solution. This solution injected intravascularly in 

 small doses in dogs produces a hindering of the coagulation of the blood 

 (Wooldridge's negative phase). In larger doses it produces intravascular 

 coagulation. 3 



The lecithin found associated with Wooldridge's tissue nbrinogens is 

 variable in quantity, and does not appear to be organically united to them. 

 After its removal the nucleo-proteids continue to exercise their most distinctive 

 physiological characteristic, in producing intravascular clotting. 4 



In connection with nucleins and nucleo-proteids, it should be men- 

 tioned that many of them contain iron, and, according to Bunge, 5 con- 

 stitute in foods the normal supply of iron to the body ; in this sense he 

 has called them hsematogens. The composition of haernatogen from egg- 

 yolk he gives in percentages, which may be compared with the com- 

 position of nuclein from yeast, as follows : 



Haematogen. Nuclein from Yeast. 



. C ... 42-11 40-81 



H . . . 6-08 5-38 



N 14-73 15-98 



... 31-05 31-26 



S 0-55 0-38 



P 5-19 6-19 



Fe 0-29 



1 Ztschr. f. pliysiol. Chem.. Strassburg, Bde. xviii. and xx. 



2 " Weitere Beitr. z. Blutlehre," Wiesbaden, 1895. 



3 Details with reference to the influence of nucleo-proteids on blood coagulation are 

 given in the article dealing with that subject. 



4 Halliburton and Brodie, Journ. Physiol., Cambridge and London, 1894, vol. 

 xvii. p. 135. 



5 Ztschr. f. physiol. Chem., Strassburg, 1884, Bd. ix. S. 49. 



