18 



THE CELL 



By the influence of a low temperature on the cell of Spirogyra caught in 

 the act of division, Gerassimow succeeded in driving all the nuclear substance 

 into one daughter cell, leaving the other quite devoid of a nucleus. In a 

 series of such experiments it was seen that in twenty-one days the growth 

 of the enucleated cells amounted to 0.44.5 per cent of the average growth 

 of the normal cell, while the growth of the cells with a surplus of nuclear 

 material exceeded that of the normal cells by as much as seventy-eight per 



\ 



FIG. 15. A radiolarian, Thalassicola nudeata, after Verworn. Cross section of a normal indi- 

 vidual. The layers from without inward are : the corona of radial pseudopodia, the gelat- 

 inous layer, vascular layer, pigmented sheath about the central capsule, and the central cap- 

 sule (in the center). 



cent. At the same time the solution, of starch in the enucleated cells either 

 did not take place at all or proceeded very feebly; the outer cell membrane 

 was less extensible than usual; the color of the chlorophyll bands became 

 constantly paler and their contour less clear. 



While the nucleus is thus of the greatest importance for the normal activity 

 of the protoplasm, it cannot maintain an independent existence. When the 

 protoplasm is paralyzed with narcotics the nucleus may indeed continue its 

 movements (Demoor), showing itself quite as independent of the protoplasm 

 as the protoplasm is of the nucleus. Nevertheless, if removed entirely from 

 the protoplasm, even if it be entirely uninjured by the manipulation and 

 be protected from all external disturbances, as has been done in the case of 

 the great radiolarian, Thalassicola (Fig. 15, Verworn), the nucleus invariably 

 perishes without exhibiting any trace of regeneration. Nor do nuclei ever 



