CHAPTER III 

 PROTOPLASM AND THE CELL 



Living- Matter, or Protoplasm 



Little is known concerning the origin of living matter, or proto- 

 plasm, as it is called, but more and more is being learned about its 

 nature, characteristics, structure, and activities. Living matter is 

 ahvays active in some degree, and this activity attracted the atten- 

 tion of scholars at a rather early date, but serious study of the 

 material was not begun until approximately one hundred years ago. 

 A Frenchman by the name of Dujardin, in 1835, realized that some 

 of the simple microscopic animals he was studying were composed 

 of a soft, gummy substance and called it sarcode, which means 

 "flesh." He was able to test its solubility and its behavior with 

 alcohol and acids sufficiently to satisfy himself that it differed from 

 ordinary gelatin or albumin, with Avhich it might be confused. In 

 1840, Purkinje, a Bohemian biologist, gave living matter the name 

 protoplasm, which comes from the Greek protos, first, and plasma, 

 anything formed or molded. In 1846 von Mohl, a German botanist, 

 saw in plants a granular, viscous substance similar to that already 

 seen in animals', and called it protoplasm. He was instrumental in 

 bringing this name into common use. During these years it had 

 gradually dawned on biologists that this matter is found in all liv- 

 ing things. 



The Cell Principle 



Cells had been seen and even superficially described during the 

 latter part of the seventeenth century and numerous times during 

 the eighteenth century, but their significance was not realized. 

 Hooke, an Englishman, in 1665 in observing cork with the micro- 

 scope he had made, saw the spaces in it and called them cells be- 

 cause they reminded him of prison cells. This name later came to 

 be applied to the real cells. It was an unfortunate term, for cells 

 do not have a hollow structure but are typically semisolid bodies. 

 Leeuwejihoek saw spermatozoa and bacteria and included them with 

 single-celled animals as "little beasties"; Malpighi had described 



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