404 PROPERTIES AND FUNCTIONS 



have seen how nearly the simple plant resembles the 

 most imperfect animal ; yet what a wonderful and mani- 

 fest difference there is between the physical properties 

 of the polypus (which belongs to the lowest order of ani- 

 mals) and man, the most perfect and complicated of all 

 organized beings. 



Each order of animals which fill up the space, has 

 some one property as it advances towards man in addi- 

 tion to those possessed by the order below it. 



Man, although he is placed entirely und absolutely 

 distinct from the whole organic creation by his intellec- 

 tual powers, by his knowledge of the principles of vice 

 and virtue, by his moral accountability, and by his con- 

 fidence of a still higher destiny than this life can afford ; 

 yet he is subject to the same physical wants that distin- 

 guish the lowest order of animals. He requires food as 

 well as they, and in both it must pass through a similar 

 process before it can form a part of themselves. There 

 must be a set of vessels to convey the fluids from one 

 part of th6 body to another in both one requires the 

 influence of the atmospheric air as well as the other, and 

 you can trace through all their organic functions a like ' 

 similarity. It is these functions together with the or- 

 gans that perform them, which we will now describe. 



All organic substances require food for the nourish- 

 ment and development of their various organs. Accord- 

 ingly all are supplied with apparatus by which the 

 food is taken and converted into its appropriate texture. 

 Most plants receive their nourishment from the earth. 

 This nourishment is taken up by vessels situated in their 

 roots, and is conveyed by other vessels prepared for the 

 purpose, to the extreme part of the leaves, where it un- 

 dergoes the process of digestion or assimilation, and is 

 converted into a substance fit for their growth. From 

 the leaves the assimilated fluid is conveyed to all parts of 

 the plant, arid by appropriate organs is changed into a 

 part of itself. If there is any excess or waste substance 

 this is carried off from the plant by vessels prepared for 

 that purpose. The arrangement of vessels in animals is 

 precisely upon the same plan as in plants, only in the 

 former they are mote complex. 



