CHEMICAL RELATIONS OF NUCLEUS AND CYTOPLASM ■'-^n 



gave the name nnclei)iic acid, and (2) a form of albumin. Moreover, 

 the nuclein may be synthetically formed by the re-combination of 

 these two substances. Pure nucleinic acid, for which Miescher ('96) 

 afterward gave the formula C^oH-^N^^P^O.,-,! contains no sulphur, a 

 high percentage of phosphorus (above 9%). and no albumin. By 

 adding it to a solution of albumin a precipitate is formed which 

 contains sulphur, a lower percentage of phosphorus, and has the 

 chemical characters of " nuclein." This indicates that the discord- 

 ant results in the analyses of nuclein, referred to above, were 

 probably due to varying proportions of the two constituents ; and 

 Altmann suggested that the " nuclein " of spermatozoa, which contains 

 no sulphur and a maximum of phosphorus, might be uncombined 

 nucleinic acid itself. Kossel accordingly drew the conclusion, based 

 on his own work as well as that of Liebermann, Altmann, Malfatti, 

 and others, that " what the histologists designate as chroviatin con- 

 sists essentially of combinations of nucleinic acid with more or less 

 albumin, and in some cases may even be free nucleinic acid. The 

 less the percentage of albumin in these compounds, the nearer do 

 their properties approach those of pure nucleinic acid, and we may 

 assume that the percentage of albumin in the chromatin of the same 

 nucleus may vary according to physiological conditions." ^ In the 

 same year Halliburton, following in part Hoppe-Seyler, stated the 

 same view as follows. The so-called " nucleins " form a series lead- 

 ino" downward from nucleinic acid thus : — 



*t) 



(i) Those containing no albumin and a maximum (9-10%) of phos- 

 phorus (pure nucleinic acid). Nuclei of spermatozoa. 



(2) Those containing little albumin and rich in phosphorus. Chro- 



matin of ordinary nuclei. 



(3) Those with a greater proportion of albumin — a series of sub- 



stances in which may probably be included /j;r;//// (nucleoli) 

 and plastiji (linin). These graduate into 



(4) Those containing a minimum (0.5 to 1%) of phosphorus — 



the nucleo-albumins, which occur both in the nucleus and in 

 the cytoplasm (vitellin, caseinogen, etc.). 



Finally, we reach the globulins and albumins, especially character- 

 istic of the cell-substance, and containing no nucleinic acid. "We thus 

 pass by a gradual transition (from the nucleo-albumins) to the other 

 proteid constituents of the cell, the cell-globulins, which contain no 

 phosphorus whatever, and to the products of cell-activity, such as 

 the proteids of serum and of egg-white, which are also principally 



^Derived from analysis of the salmon-sperm. "^'93. P- 'S^. 



