PSYCHIC GRADATIONS. 121 



— This third and higher stage of presentation is the 

 commonest form the function takes in the animal 

 world ; it seems to be a localisation of presentation 

 in definite " soul-cells." In its simplest form it 

 appears at the sixth stage of reflex action, when the 

 tricellular reflex organ arises : the seat of presentation 

 is then the intermediate psychic cell, which is inter- 

 posed between the sensitive cell and the muscular 

 cell. With the increasing development of the animal 

 nervous system and its progressive differentiation 

 and integration, this unconscious presentation also 

 rises to higher stages. 



IY. Conscious presentation in the cerebral cells. — 

 With the highest stage of development of the animal 

 organisation consciousness arises, as a special func- 

 tion of a certain central organ of the nervous system. 

 As the presentations are conscious, and as special 

 parts of the brain arise for the association of these 

 conscious presentations, the organism is qualified for 

 those highest psychic functions which we call thought 

 and reflection, intellect and reason. Although the 

 tracing of the phyletic barrier between the older, 

 unconscious and the younger, conscious presentation 

 is extremely difficult, we can affirm, with some degree 

 of probability, that the evolution of the latter from the 

 former was polyphyletie [that is to say, took place 

 along a number of independent lines] ; because we find 

 conscious and rational thought, not only in the highest 

 forms of the vertebrate stem (man, mammals, birds, 

 and a part of the lower vertebrates), but also in the 

 most highly developed representatives of other animal 

 groups (ants and other insects, spiders and the higher 

 crabs among the articulate, cephalopods among the 

 mollusca) . 



