IÔ2 
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 rôle of the nuclein in the division 
of the nucleus has been demonstrated by staining methods, but 
it may also be inferred from observations on algæ 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 (3) and even growth of the cells to a considerable size 
will take place, but 710 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 karyokinesis, 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 , Gruber). 
That the growth of vegetal cells bears a certain relation to the 
(1) According to E. 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) Liebermann showed that nuclein contains metaphosphoric acid, and Kossel, 
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 Lociv , On the 
functions of calcium and magnesium salts in plants, Flora, 1S92, 368 ; Landw, 
Versuch-Stat. 41 , 467. 
(3) Traces of potassium salts are probably always stored up in the plant-cells. 
