THE CELL AND PROTOPLASM. 91 



parts being entirely subordinate, and indeed fre- 

 quently absent. A cell was thus a bit of proto- 

 plasm, and nothing more. But the more im- 

 portant feature of this doctrine was not the 

 simple conclusion that the cell substance consti- 

 tutes the cell, but the more sweeping conclusion 

 that this cell substance is in all cells essentially 

 identical. The study of all animals, high and 

 low, showed all active cells filled with a similar 

 material, and more important still, the study of 

 plant cells disclosed a material strikingly similar. 

 Schultze experimented with this material by all 

 means at his command, and finding that the 

 cell substance in all animals and plants obeys 

 the same tests, reached the conclusion that the 

 cell substance in animals and plants is always 

 identical. To this material he now gave the 

 name protoplasm, choosing a name hitherto given 

 to the cell contents of plant cells. From this 

 time forth this term protoplasm was applied 

 to the living material found in all cells, and 

 became at once the most important factor in the 

 discussion of biological problems. 



The importance of this newly formulated 

 doctrine it is difficult to appreciate. Here, in 

 protoplasm had been apparently found the 

 foundation of living phenomena. Here was a 

 substance universally present in animals and 

 plants, simple and uniform a substance always 

 present in living parts and disappearing with 

 death. It was the simplest thing that had life, 

 and indeed the only thing that had life, for there 

 is no life outside of cells and protoplasm. But 

 simple as it was it had all the fundamental pro- 



