CELL THEORIES. 123 



chareacters of protoplasm and distinct from the 

 nucleus. 



One of the short-comings of Professor Strieker's 

 article on the general character of cells is that he 

 exaggerates the virtue of the protoplasm. He uses 

 the expression, " Protoplasm is termed a living 

 substance," or, as the German (man bezeichnet) 

 may be more strictly translated, " it is recognized 

 as a living substance ; " and he speaks in such a 

 way as to leave the impression that it is a definite 

 chemical compound. Now, the fact is that proto- 

 plasm when examined under the microscope, is 

 usually as thoroughly dead as anything could be 

 well imagined to be. Living masses of protoplasm, 

 no doubt, can be studied microscopically, and a 

 great stride has been made in science by the ex- 

 amination of such masses in texture ; but the com- 

 position of the protoplasm is not definitely known. 

 It is quite unobjectionable to call the albuminoid 

 mass of a nucleated corpuscle protoplasm, even 

 after it has been acted on by means of chromic 

 acid, carmine, or other reagents. In fact, proto- 

 plasm is simply a convenient name to use in speak- 

 ing of the pulpy nitrogenous substance of vital 

 corpuscles ; but it is not to be forgotten that the 

 substance referred to is variable in appearance and 

 behaviour, as is well illustrated by Heidenhain's 



