THE CELL AND PROTOPLASM. 69 



an explanation of these, we have explained the 

 living machine. If we grant that certain parts of 

 the body can assimilate food and multiply, having 

 the power of contraction when irritated, we can 

 readily explain the other functions of the living 

 machine by the application of these properties to 

 the complicated machinery of the body. But these 

 properties are fundamental, and unless we can 

 grasp them we have failed to reach the centre of 

 the problem. 



As we pass from the more to the less compli- n 

 cated animals we find a gradual simplification of 

 the machinery until the machinery apparently 

 disappears. With this simplification of the 

 machinery we find the animals provided with 

 less varied powers and with less delicate adapta- 

 tions to conditions. But withal we find the 

 fundamental powers of the living organisms the 

 same. For the performance of these fundamental 

 activities there is apparently needed no machinery. 

 The simple types of living bodies are simple in 

 number of parts, but they possess essentially the 

 same powers of assimilation and growth that 

 characterize the higher forms. It is evident " 

 that in our attempt to trace the vital properties 

 to their source we may proceed in two ways. 

 We may either direct our attention to the 

 simplest organisms where all secondary machinery 

 is wanting, or to the smallest parts into which 

 the tissues of higher organisms can be resolved 

 and yet retain their life properties. In either 

 way we may hope to find living phenomena 

 in their simplest form independent of secondary 

 machinery. 



