CHAPTER III. 



LIVING MATTER OR PROTOPLASM. 



IT is evident from the last chapter that protoplasm must be 

 the starting-point for detailed studies of organisms such as we 

 are soon to enter upon, or indeed for biological studies of any 

 kind. The present chapter will therefore be devoted to a gen- 

 eral account of protoplasm, beginning with a sketch of its dis- 

 covery and afterward discussing its characteristic appearances 

 and structure, its properties, chemical basis, and relations to 

 various physical agents, such as heat, light, electricity, etc. 



Historical Sketch. Protoplasm was observed long before its 

 significance was understood. The discovery of its essential iden- 

 tity in plants and animals, and ultimately of the extreme impor- 

 tance of the role which it everywhere plays, must be reckoned as 

 one of the greatest scientific achievements of this century. 



Dujardin, in 1835, applied the name sarcode (<TapKGd8r],fles?iy} 

 to certain forms of living matter forming the bodies of some of 

 the simplest animal organisms ; but the wordprotoplasm^pdoTOi:, 

 first; 7tXaafj.a^form) was first used by Von Mohl in 1846 to des- 

 ignate a portion of the contents of vegetal cells, though he was 

 ignorant of its full significance. In 1850 Cohn definitely main- 

 tained the essential identity of the " sarcode" of the zoologists 

 and the " protoplasm" of the botanists, a view which had already 

 been propounded in different words by Payen four years before. 

 Scientific research advanced rapidly to the discovery which now 

 lies at the root of biology, viz. : that life is a manifestation of 

 this remarkable substance, essentially identical in chemical, 

 physical, and other properties, in all plants and animals. To 

 Max Schultze belongs the credit of having given the first com- 

 prehensive statement of this identity (I860), and he is now gen- 

 erally recognized as the founder of biology in the modern sense. 

 He first extended the meaning of the word protoplasm to in- 

 clude all living matter, both vegetal and animal, in which sense 

 the word is now universally employed. 



