10 PROTOPLASM 



workers that a protein complex is the ultimate living substance. 

 The constituents of this complex are probably of the nature of 

 enzymes or organic catalysts. 



The opposing viewpoint rests on the assumption that no 

 distinction exists between the living and the nonliving in proto- 

 plasm, that the living substance is alive because it is an organized 

 system the component parts of which are lifeless when considered 

 individually but when associated in a coordinated state, life 

 results. Hopkins says, ''We can scarcely speak at all of living 

 matter in the cell. At any rate we cannot , . . speak of the 

 cell life as being associated with any particular type of molecule. 

 Its life is the expression of a particular dynamic equilibrium 

 which obtains in a polyphasic system. Life ... is a property 

 of the cell as a whole." One must, of course, agree with Hopkins' 

 further remark that "the integrity of metabolic life of a liver cell 

 is as much dependent on the existence of the metaplasmic glyco- 

 gen, however small in amount, as upon the existence of the 

 nuclear material itself." So also is the running locomotive 

 dependent upon its fuel of coal and water, but the ultimate 

 mechanism is a structure of steel. Living protoplasm has its 

 fuel and a mechanism for converting the fuel into potential 

 energy. Wilson agrees with Hopkins in saying, "The term 

 protoplasm does not designate a single substance but is a col- 

 lective name for the sum total of the active components that 

 cooperate in the work of a complex system ; and life -is the sum 

 total of the activities of that system." Sharp believes it to be a 

 fundamental fallacy to attribute the properties of a system to one 

 or more of its constituent elements. Mast is equally firm in this 

 belief. He states, "If, then, protoplasm is defined as living 

 substance, its structure must involve the cell as a whole, not . . . 

 this portion or that portion." So we conclude from this view- 

 point that any substance acquires the property of life when it 

 becomes part of a living system. 



The opposing belief in a basic substance also carries with it 

 the concept of protoplasm as a living system. If there is some 

 one substance or a complex of substances which represents 

 ultimate living matter, then it can maintain life only when it is 

 surrounded by and intimately associated with its environment of 

 water, fats, etc. One might compare protoplasm to a larger 

 living system, such as a plant, where it is clear that the waxy 

 cuticle of the leaves, the bark, the stored food, the resin, the latex, 



