52 EVOLUTION OF MIND 



essentially the same in plants, the lower animals, and man ; 

 and such a multiplication of terms will only still further 

 confuse a subject already rendered needlessly intricate by 

 man's ingenious refinements in word-splitting. 



Though our present knowledge is fragmentary and un- 

 precise, it is nevertheless desirable to attempt a general 

 sketch of the kind and amount of data we possess, upon or 

 from which to begin the construction of a future science of 

 comparative psychology. It is proper to expose our ignorance 

 and deficiencies, in order to point out to the student the 

 direction in which research is desirable and likely to yield 

 profitable results. 



Beginning with the lowest subkingdom of the Inver- 

 tebrata the Protozoa of zoologists certain of the Infusoria, 

 or Rhizopoda, according to Dr. Carter, exhibit will, deter- 

 mination, fixed purpose or aim, intention, cunning, in- 

 genuity in the adaptation of means to an end, the re- 

 cognition of food and the selection thereof. The Vorticella 

 is said to ' contract itself upon its stem when alarmed or 

 irritated ' (' Globe Encyclopedia ') , Among the Rhizopoda 

 Carpenter refers to the selection of the materials of con- 

 struction by and to constructive art in Amoeba; while 

 Houzeau mentions way-finding to food supply in Actinophrys ; 

 and Carter assigns to both animals observation, will, and 

 intention in their food-search. Pouchet speaks of the 

 Amoeba the so-called proteus animalcule changing its 

 shape ' at will.' In the Protozoa feeling is excited by 

 external impressions. 



Here we have, then, at the very base or beginning of the 

 zoological scale, in the capture of prey a whole series of mental 

 phenomena exhibited will, purpose, choice, ingenuity, obser- 

 vation, feeling ; and these aptitudes doubtless involve others, 

 such as sensation and consciousness, patience and perse- 

 verance. It seems incontestable that choice or preference 

 in the selection of food is a characteristic of the very lowest 

 animals. And if this be the case, certain at least of the 

 mental qualities above specified with others are necessa- 

 rily involved. 



Ascending a stage higher, among the Coslenterata we have, 



