376 THE BIOCOSMOS PARTICULARIZED. 



so important in Geography. A second halv- 

 ing of the Earth into symmetrical parts is 

 made by the ecliptic, whose inclination to the 

 equator is nearly twenty-three and a half de- 

 grees. Another symmetrical halving of the 

 Earth is that of day and night produced by 

 axial rotation, and hence is not fixed but con- 

 tinuous, and also self-returning every twenty- 

 four hours. Earth-life as a whole may thus 

 be deemed half asleep and half awake, spa- 

 tially and temporally, contrasting therein with 

 Plant and Animal whose sleeping and waking- 

 involve the whole individual, not the half of 

 him; or he is entirely in the light 6r entirely 

 in the night, not in both at once. 



The symmetry of the Earth is, according- 

 ly, of the two hemispheres, not of the two 

 sides (like the Animal) or of the two ends 

 (like the Plant). Spherical symmetry is the 

 simpler and more immediate, being equally 

 possible in many divisions, as an apple can 

 be halved in numerous ways. Lateral sym- 

 metry of animals has but one true median 

 line of separation; terminal symmetry of 

 plants has essentially but one way parting the 

 two symmetrical ends (roots and branches, 

 including leaves). Still in the three forms of 

 Life Plant, Animal and Earth we are to 

 note the common principle of dual symmetry. 



3. The Earth - organism differentiated. 



