554 THE POPULAR SCIENCE MONTHLY 



to those of the human mind. With respect to the development of sur- 

 plus energy, however, it matters little whether Jennings's affirmation 

 or Loeb's denial of consciousness is right. It is perfectly clear that the 

 structural change represented by the difference between Amoeba and 

 Paramecium permits greater adaptation of the individual to its environ- 

 ment and, other things equal, tends to permit a greater expenditure of 

 energy in non-sustaining activity. Further improvements in structure 

 encountered as we proceed higher in the scale of evolution likewise 

 imply greater adaptation and still greater surplus. 



Before leaving Paramecium to discuss behavior of a distinctly more 

 advanced type one more point of special interest to the sociologist must 

 be noted. This is the fact that Paramecia in their individual efforts 

 to find the optimum environment are brought into physical proximity. 

 Further, it has been demonstrated that for certain individual Paramecia 

 the optimum seems to be created, other things being equal, by the 

 presence of carbon dioxide. Inasmuch as carbon dioxide is produced 

 by the Paramecia themselves, this means that such Paramecia not only 

 tend to form groups, but indirectly to influence the behavior of each 

 other. If subjective phenomena accompany response to stimulation by 

 carbon dioxide we have here a state of consciousness modified by the 

 presence of organisms of like kind, even if there is, strictly speaking, no 

 consciousness of kind — that is, even if there is no recognition of the 

 presence of another of its own kind by the animal. The formation of 

 groups by Paramecia as a result of their own production of carbon 

 dioxide, according to Jennings, explains many peculiar phenomena in 

 their behavior. For example, Paramecia in a solution of carbon dioxide 

 react to other agents in a manner entirely different from the action of 

 individuals in water not containing carbon dioxide. Now membership 

 in a group is often an important protection to the individual. It is, 

 therefore, often a factor in survival and is of importance in the pro- 

 duction of a surplus. 



The important facts to be noted up to this point are, first that 

 change in structure may mean more complex behavior and an increased 

 surplus, and second, that congregation if not association modifies both 

 behavior and safety and this also affects surplus. 



In Stentor roeselii there enters a new factor affecting surplus. This 

 is the modification of behavior because of past experience. Stentor 

 roeselii is a colorless or whitish trumpet-shaped water-inhabiting animal 

 consisting of a slender stalk-like body bearing at its end a broadly ex- 

 panded disk. The surface of the body is covered with cilia. The smaller 

 end of the body is known as the foot and at this end fine pseudo- 

 podia are sent out by which the animal attaches itself. The lower half 

 of the body is surrounded by the so-called tube or sheath formed by a 

 mucus-like secretion from the surface of the body. If, now, some such 



