21ie Organism and Its Cells 155 



tation of its cells, as the cells are to the interpretation of 

 the organism. A brief excursion into the liistory of the 

 cell-theory is essential to the discussion. 



It is well known that the early workmen on the cell- 

 theory had quite erroneous notions of the nature of cells. 

 The error has, unfortunately, left its conspicuous and in- 

 eradicable mark on biology in the term cell. This name 

 was chosen from the circumstance that the first studies were 

 made on grown plants where the cell-wall is the most easily 

 observable part of the cell, so that the ctlls frequently ap- 

 pear like vesicles either quite empty or containing a clear 

 fluid or semi-fluid. Cells were closed chambers the walls of 

 which were the main thing, according to tliese pioneering 

 views. For a long time the nature, structural and func- 

 tional, of the contents of these chambers played only a 

 subordinate part. Gradually, however, from widely scat- 

 tered observations, partly on the simplest unicellular or- 

 ganisms, partly on the contents of certain simple plant cells, 

 and partly on the tissues of higher animals, it dawned upon 

 biologists that the material within the cell-wall is the main 

 thing, and that this material is much the same in all cells, 

 whether plant or animal, of low or high degree. The pro- 

 toplasm of Purkinje and Von Mohl, the sarcode of Dujardin, 

 the "cell sap" of Corti and Treviranus, and the "plant 

 nmcilage" of Schleiden, were all brought together because 

 of their close resemblance and designated by a single name. 

 On account of the seeming simplicity of this material and 

 tlie undoubted dependence of life phenomena upon it, pro- 

 toplasm is the designation now almost universally applied 

 to it. To Max Schultze, writing in 1861, belongs the credit 

 more than to any other one man, of comprehending the 

 nature of cells as we now understand them, and the terminol- 

 ogy in which Oscar Hertwig expresses Schultze's achieve- ■ 

 ment is of prime significance. Although Schultze retained 

 the name cell, naturalized in anatomy by Schleiden and 



