THE WONDERS OF LIFE 



which are mostly brought about by chemical stimuli (to 

 a small extent by mechanical and other irritation) in the 

 organs themselves. As subjective feelings of the or- 

 ganism itself these states are most aptly called "feelings" 

 — the positive states, pleasure, comfort, delight; the 

 negative, discomfort, pain, etc. These organic sensa- 

 tions (also called common sensations or feelings) are of 

 great importance for the self-regulation of the complicat- 

 ed organism. To the positive organic sensations belong 

 not only the bodily feeling of satiety, repose, or comfort, 

 but also the psychic feelings of joy, good humor, mental 

 rest, etc. Among negative common feelings we have 

 not only hunger and thirst, bodily fatigue, bodily 

 pain, sea-sickness, etc., but also mental strain, vertigo, 

 bad humor, and so on. Between the two groups we 

 have the third category of neutral organic sensations, 

 which involve neither pleasure nor pain, but merely the 

 perception of certain internal conditions, such as mus- 

 cular strain (in lifting heavy objects), the disposal of the 

 limbs (in crossing the legs), and so on. 



Chemical sensation is just as general and important in 

 organic nature as in the life of organisms. In this case 

 it is nothing less than the basis of chemical affinity. No 

 chemical process can be thoroughly understood unless we 

 attribute a mutual sensation to the atoms, and explain 

 their combination as due to a feeling of pleasure and 

 their separation to a feeling of displeasure. The great 

 Empedocles (fifth century b.c.) explained the origin of 

 all things long ago by the various combination of pure 

 elements, the interaction of love (attraction) and hate 

 (repulsion). This attraction or repulsion is, of course, 

 unconscious, just as in the instincts of plants and 

 animals. If one prefers to avoid the term "sensation," 

 it may be called "feeling" (cssthesis), while the (involun- 

 tary) movement it provokes may be called "inclination " 

 {tropesis), and the capacity for the latter "tropism" 



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