.-•..- -.-.v.- --:/.., •-.•.••.^. .. _.:• . '.•.•?r...-r •.:•;•• .-•.-'••■.' 



\1' 





PROTOPLASM MOVES 



In many types of cells that have been studied, we can see portions of the fluid stream- 

 ing or circulating about, as suggested by the arrows 



same in some respects, but always capable of changing as circumstances 

 change. Fundamentally the same in all organisms, it is in every particular 

 case distinct and peculiar. That is characteristic of protoplasm, as it is char- 

 acteristic of life. 



At any rate, scientists are pretty well agreed that it is this protoplasm of 

 a plant or a kitten that grows. It is protoplasm in the body of the Venus's 

 fly-trap or of 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 light. 



In Brief 



Plants and animals take in food and grow by assimilation; nonliving 

 objects grow only by accretion. 



Living plants and animals move through processes going on inside the 

 organisms, while inorganic objects are pushed around by outside forces. 



Living things are irritable, or sensitive to changes in their surroundings. 



The responses of living things to disturbances are generally adaptive; 

 that is, they tend to help living things to keep on living. 



Living things originate from others of the same kind, and may produce 

 offspring like themselves. 



Living things consist of special parts, or organs, that carry on distinct 

 services or functions, 



26 



