LOWER FORMS OF LIFE. 25 



the animal. Poetically regarded, the plant is the passive 

 organism as described by Riickert : 



•• I am the garden flower 

 And meekly bide the hour, 

 The guise, with which you come 

 Within my narrow room." * 



The antithesis of the passive, quiescent plant and the 

 pugnacious active animal diminishes, however, as we 

 descend in the scale of both kingdoms. The more 

 highly developed animal evinces its animal nature by 

 the vivacity with which it reacts to external influences 

 and excitations. In the lower animals the phenomena 

 of life assume a more vegetal character, and in many 

 groups of lower beings, which Haeckel has recently 

 comprised under the name Protista, we see the pro- 

 cesses of metamorphosis of tissue, nutrition, and repro- 

 duction taking place, indeed, but in a manner so simple 

 and undifferentiated, that we too must attribute to these 

 beings a neutral position betwixt plants and animals. 

 We gain the conviction that the roots of the vegetal 

 and animal kingdoms are not completely sundered, but, 

 to continue the simile, merge imperceptibly into each 

 other by means of a connective tissue. In this inter- 

 mediate kingdom the much derided " primordial slime '* 

 (Urschleim) of the natural philosophers has regained 

 its honourable position. Many thousand cubic miles of 

 the sea-bottom consist of a slime or mud composed in 

 part of manifestly earthy inorganic portions, in part of 



* " Ich bin die Blum' im Garten 

 Und muss in Demuth warten, 

 Wann und auf welche Weise 

 Du trittst in meine Kreise." 



