cii Journal of Comparative Neurology. 



It is thought that we may safely conclude : 



1. Wherever there is a central nervous system, there we find a con- 

 sciousness. 



2. Consciousness may be traced backward, through animals with 

 simple nervous systems, to animals with none at all. 



3. An absolute boundary between consciousness and unconscious- 

 ness cannot be drawn. Probably consciousness begins with the dawn of 

 life. 



4. Probably the evolution ot the soul goes hand in hand with the 

 evolution of the nervous system. 



General Feeling the Function of Mind in the Phylogenetic 

 Development. The movements of the sensitive plants are due to me- 

 chanical stimuli. The turning of plants to the light is due to the effect 

 of light. The opening of some flowers during the day and of others 

 during the night is due to chemical stimuli originated by light. 1 In in- 

 sectivorous plants, the folding of the parts is mechanical, but the resting 

 of the organ in a folded state is a secondary acquirement. 2 



If we regard insectivorous plants as conscious beings then we must 

 introduce between the mechanical stimulus and the capturing movements 

 and digestive activities a psychical state. Such a state corresponds to the 

 appetite aroused in us by the odor of a good meal ; or, better still, by the 

 appetite aroused in the new born babe by the proximity of its mother's 

 breast. This would be a general feeling aroused by chemical stimuli. 

 These observations show that plants have states which prefigure the con- 

 scious states of the lower animals. It must be carried in mind, however, 

 that plants have no semse-perceptions. They have no sense organs, and 

 sense organs are essential to sense-perceptions. 



In the lowest protozoa, the monera of Haeckel, consciousness can 

 scarcely be said to be more highly developed than in the plants. Here 

 then we find feelings only and no setise-perceptions. Indeed, how could 

 they. have sense-perceptions? To develop a sense two factors must come 



1. It seems as though there is something more than this. Is there enough differ- 

 ence in the chemical constitution of different plants to warrant such opposite reac- 

 tions to the same stimuli ? 



2. Kroener seems to ignore the fact that insectivorous plants contract under the 

 stimulus of nitrogenous material, and that the continued excitation due to the pres- 

 ence of this food retains the parts in a contracted state until the nitrogenous material 

 ia digested. 



