BIOLOGICAL POSITION OP MAN 37 



(d) Power to dissolve and distribute food. 



(e) Power to transform absorbed food into new pro- 

 toplasm. 



(/) Power to remove waste matter. 



(g) Power to take in air and give off carbon dioxide. 



A review of these properties shows that protoplasm 

 performs in a simple way practically all the actions that 

 we perform as human beings. If we recall that all cells 

 contain protoplasm, and that tissues are made of cells, 

 organs of tissues, and systems of organs, it is evident that 

 the activity of this protoplasm must be very closely re- 

 lated to the actions of the organs and systems themselves, 

 and hence to the activities of the organism that contains 

 these systems. 



Biological position of man. — Botanists and zoolo^sts 

 (who study plants and animals) tell us thsit ~there are 

 thousands of different kinds of plants and animals, but 

 that when we examine the structure of these many forms 

 of living matter, all are found to be capable of reduction 

 to a common structural unit (the cell) and a common 

 structural substance (the protoplasm). Furthermore, 

 they tell us that the only essential difference in structure 

 between high and low plants and animals is to be found 

 in the greater number, kind, and complexity of arrange- 

 ment of the cell units in the higher forms, as compared 

 with the simpler arrangement, kinds, and numbers in the 

 lower forms. Man, therefore, is to be considered as an 

 animal composed of many cells of different kinds and 

 action. He is placed highest in the living kingdom be- 

 cause in him we have a cellular organism in its highest 

 development. 



