THE MECHANISM OF LIFE 



569 



ment of animals. This designation is correct, but the government 

 of the cell-communities of plants, sponges, and hydroid polyps is 

 not the primitive form of a republic, which has been seen in the 

 colonies of the Protista. We find here no longer the power of the 

 individual cell to exist by itself apart from association with the 



FIG. 273. /, Carchesium polypinum, a stalk of Ciliata. A, The individuals are extended upon their 

 stalks. B, The individuals have contracted as the result of a shock. //, A, Eudorina degans 

 a colony of Flagellata ; B, Magosphcera .planula, a colony of Ciliata. (After Haeckel.) 



others. Dependence upon the other cells is too great, but small 

 groups of cells can maintain themselves and live separately. E.g., 

 as Vochting ('85) has shown, the leaves of many plants can be cut 

 into minute pieces and from them whole plants can grow, and 

 likewise, as has been seen (Fig. 2, p. 57), every piece of a Hydra, 

 that has been cut up is capable of independent life. 



