THE LIVING STUFF 



21 



that bodies organized in such very different ways come to be 

 so much alike in those three points that are said to distinguish 

 living things from non-living ? 



34. Protoplasm. The answer to this 

 question is to be found in the fact that 

 in the bodies of all organisms there is 

 a peculiar substance (or rather a mix- 

 ture of substances) which seems to 

 have all the qualities of living bodies. 

 This seems to be the stuff that can 

 grow ; this is the stuff that moves ; this 

 is the stuff that is irritable. When 

 seen under the microscope this living 

 stuff seems to be a slimy, or jellylike, 

 substance something like the white 

 of egg in appearance. Under a more 

 powerful microscope it sometimes ap- 

 FIG. 2. Protoplasm moves P ears to have man 7 minute bubbles in 

 The arrows indicate the stream- k or to consist of an extremely fine 

 ing of the protoplasm within network. This stuff is called proto- 



the cells . 



plasm, and in all essential respects 

 it seems to be alike in all plants as well as in all animals. 



It is the 

 protoplasm of 

 a plant or of 

 a kitten that 

 grows. It is 

 protoplasm in 

 the body of 

 the Venus's 



FlG- 3> Diagram of a cell 

 flytrap Or OI 

 a Snake that 



moves when 



the organism springs upon its victim. It is the protoplasm 



of the geranium or of the worm that is sensitive to the light. 



mass O f t he cell content consists of the protoplasmic network, 

 t ^ ie coarser-grained nucleus. Within the protoplasm are more 

 solid bodies, and droplets of more liquid substances 



