212 THE BIOCOSM08 PARTICULARIZED. 



range of the Diacosmos, fluid, radiant, and 

 chemical, transforming it into the vital 

 sphere or the Biocosmos. The Plant, then, 

 largely through its leaf reveals itself as sub- 

 ordinating the whole separative domain of 

 Nature, and making it over, into the rounded 

 process of Life, the next higher stage. We 

 hail the appearance of the doctrine of lielio- 

 tropism in recent botany, but it must be vast- 

 ly extended, and more deeply interpreted. 

 The turn of the Plant to the sun (heliotrop- 

 ism) means far more than its turn to light, 

 important as this is. 



The leaf in itself forms a very interesting 

 and significant study of great diversity, capa- 

 ble of being ordered into the image of the to- 

 tal Plant and of all Life, yea of the Universe 

 itself in small. First the leaf differentiates 

 itself into an upper sunward surface, and a 

 lower shadeward surface, then it shows a vast 

 multiplicity of shapes, outlines, sizes, quali- 

 ties, so that each tree or brush may be said 

 to have its own leaf, and this often varies a 

 good deal on the same bush or even twig. The 

 kinds of venation in the leaf (paral- 

 lel-veined and netted-veined) seem to 

 indicate a great node in the evolu- 

 tion of Plant-life, conjointly with the two 

 sorts of cotyledons. In fact the leaf may be 

 put into the line of vegetal evolution to repre- 



