132 THEORETICAL BIOLOGY 



in our appearance-world. Driesch has answered this question 

 in the affirmative. As soon as it becomes a natural factor, 

 he calls this other apperception a psychoid, in order to avoid 

 the perpetual confusion of the other psyche with our own. 

 According to Driesch, to whom we are indebted for the change 

 of trend in modem biological theory, the psyche of the 

 observer, when it investigates another subject, encounters 

 the actions of the psychoid. And these then enter into the 

 function-circles as super-mechanical factors. 



THE WORLD-AS-SENSED 



There are animals, such as the sponges, which are seden- 

 tary, and in virtue of their bodily constitution, unassailable ; 

 and for these animals a single indication suffices. They 

 cannot leave their medium, and they possess no movable 

 weapons. They simply cast their sexual products adrift. 

 Consequently they lack three of the function-circles which 

 require a special guidance and special indications. The food- 

 circle is the only one they have. But the food does not give 

 rise to an indication, for it is whirled through the body with 

 the sea-water, and carried off by the digesting-cells. Harm- 

 ful substances all have the same indication ; acids, for 

 instance, exert a chemical stimulus, sand-grains, a mechanical ; 

 these stimuli are not distinguished from one another by the 

 animal, but all call forth the same reflex. That is to say, 

 there is only one single indication in the sensed world of the 

 sponge. 



For the infusorian Paramecium, the same indication 

 suffices for the circle of the medium and for that of the food, 

 for all the stimuli that proceed from the various objects the 

 animal may meet with as it swims ceaselessly to and fro, 

 provoke it to shift the helm, as it were, and to hasten off again 

 in another direction. The only things that do not produce 



