CHAPTER IV. 



RELATIONS OF ANIMAL, VEGETABLE, AND MINERAL KINGDOMS. 

 THEORIES OF ORGANIZATION. 



The two higher Organic Kingdoms. Relations of Plants and Animals 

 to one another, and to Air, Earth, and Water. Plants produce and 

 Animals consume organic matter. Plants derive Carbon from the 

 air. Illustrations from past succession of Life on our globe. 

 Nature's Cycle. Plants continually producing Living Matter from 

 inorganic materials. 



Theories of Organization. Cells. Doctrines of Schleiden and Schwann. 

 Views of Goodsir. Virchow's Cellular doctrines. Modifications of 

 views concerning the Cell and its powers. These necessitated by 

 our knowledge of the Protista. Cells and Plastides. Dr. Pile's 

 views concerning Germinal matter and ' Formed material.' Prof. 

 Huxley's opposition to Cellular Theories. Dr. Hughes Bennett's 

 ' Molecular Theory of Organization.' Doctrine now maintained by 

 very many Physiologists. This in harmony with Evolution Hypo- 

 thesis. Reason why Cells are so common as morphological units. 

 Do they arise de novo in blastemata ? 



EAVING now for a time the consideration of 

 the nature of the lowest known forms of Life, 

 and all speculations as to the mode of evolution of 

 those combinations of matter and motion out of which, 

 by the most insensible gradations, they have gradually 

 arisen, it will be desirable to turn our attention to the 

 mutual relation of Plants and Animals to one another, 



K 



