LOWER FORMS OF LIFE. 25 
the animal. PoeticaJly regarded, the plant is the passive 
organism as described by Riickert : 
** Tam 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.” 
