l62 THE ENERGY OF THE LIVING PROTOPLASM. 



As the main constituent of the nucleus is nuclein (I) and as this 

 is essentially a combination of an albuminous substance with 

 phosphoric acid' 2 ' the importance of the latter becomes at once 

 conspicuous. The important role of the nuclein in the division 

 of the nucleus has been demonstrated by staining methods, but 

 it may also be inferred from observations on algae cultivated in 

 liquids devoid of phosphates. If we place some filaments of 

 Spirogyra majuscula in about a liter of distilled water, to which 

 has been added 0.2 p. mille calcium nitrate and 0.02 p. mille 

 ammonium sulphate, and expose the culture to diffused daylight, 

 assimilation as well as protein formation can proceed to a certain 

 extent 131 and even growth of the cells to a considerable size 

 will take place, but no multiplication of cells is noticed. Gradually, 

 however, the threads assume a yellowish tinge and commence to 

 suffer. If after about six weeks we divide the filaments, together 

 with the solution, into two portions, adding to one 0.02 p. mille 

 protosulphate of iron, to the other, besides this, 0.08 p. mille 

 disodium phosphate, we can observe in a few days, in the latter 

 case, not only the restoration of the brilliant green colour but also 

 the process of karyokincsis, in almost every cell, and this too, in the 

 daytime. In the former case, however, where the iron salt 

 alone was added, none of these phenomena was observed, 

 showing, further, that for the production of a normal chlorophyll, 

 phosphoric acid is just as important as iron salts. 



The nucleus plays also a certain part in the organisation of 

 the cytoplasm. In cases of mutilation, only such cells can be 

 regenerated as still contain the nucleus {Nussbaum, Grttber). 

 That the growth of vegetal cells bears a certain relation to the 



(1) According toE. Zaccharias, besides nuclein, plastin also occurs in the nucleus 

 and chloroplasts. Plastin appears to be mainly distinguished from nuclein by its 

 greater resistance to acids and alkalies. 



(2) IJcbcrmann showed that nuclein contains mctaphosphovic acid, and Kosscl, 

 that bases of the xanthin series and nucleic acid are contained in it. My own 

 observations make it highly probable that the nuclein in the living nucleus is present 

 as a lime compound, that is to say, in chlorophyll-bearing plants. With fungi, 

 however, it is different, lime not being at all required by them. Cf. O Locw, On the 

 functions of calcium and magnesium salts in plants, Flora, 1892, 368 ; Landw, 

 Versuch-Stat. 41, 467. 



(3) Traces of potassium salts are probably always stored up in the plant-cells. 



