228 UNIVERSITY OF COLORADO STUDIES 



reference to physical fitness. Loeb in a recent series of physiological 

 experiments 1 has shown definitely that most lower forms have no intelli- 

 gence, not even consciousness. Some very complex reactions and 

 instincts which were constantly interpreted by physiologists and psycholo- 

 gists as intelligent 2 and giving evidence of power of choice 3 and of power 

 to learn by experience, 4 are merely some form of tropism and can be 

 explained in terms of the chemical constituents of the organism. 



He explains, e. g. heliotropism in the moth on exactly the same basis 

 as that of a flower which turns toward the source of light. The stere- 

 otropism of the worm, e. g. Nereis, which seeks to bring its body into 

 contact with solid objects is exactly like that of Tubularia whose stolon 

 turns toward and sticks to solid bodies. Certain animals, e. g. actinians, 

 are geotropic and are not satisfied until they burrow into the sand just 

 as the roots of a plant which also possesses this tropism. His experi- 

 ments are convincing. These reactions are physical in their nature 

 and do not imply consciousness any more than do the reactions of a 

 root or flower. But they are elements which factor in consciousness 

 when it [consciousness] does appear. It may be possible that the wild- 

 ness reactions and migratory instincts, illustrated above, vail be found 

 to be mere tropisms, when we get a more adequate knowledge of com- 

 parative psychology. 



Hodge, from some experiments on specimens of Vorticella, attrib- 

 uted to them intelligence. He fed them yeast which they voraciously 

 devoured, but after a while spewed out. No attempt to feed them 

 yeast afterward was successful. This was interpreted as a learning 

 by experience. Loeb's experiments make another explanation possible. 

 The yeast effected a chemical change in the organism, and with refer- 

 ence to yeast produced a negative tropism. 



These tropisms, essential to the organism are seized upon and main- 

 tained. Emotion may be regarded, from the standpoint of the James- 

 Lange theory of the emotions, 5 as a form of tropism, and the following 



1 Loeb, Physiology of the Brain. 



1 Pflugf.r, Die sensorischen Functionen des RUckenmarks. 

 3 Binet, Psychic Life of Microorganisms. 



* Hodge, "Daily Life of a Protozoan," American Jour. Psychol., Vol. VI; Jennings, "The Psychology 

 of a Protozoan," ibid; Watkins, "Psychical Life of Protozoa," ibid., Vol. XL 

 s James, Principles of Psychology, Vol. II, chapter on Emotions. 



