MOVEMENTS OF PROTOPLASM 



235 



actively dividing, the protoplasm may entirely fill the 

 space and no vacuoles be present. 



386. MOVEMENTS OF PROTOPLASM. Within the cell- 

 wall, many times the protoplasm shows a tendency to move 

 from place to place. This movement is / 

 chiefly of two kinds: (1) circulation, or 



movement not only along the walls but 

 also across the cell -body, as seen in the 

 long, thin -walled cells of celandine; in 

 the staminal hairs of tradescantia (Fig. 

 386); in the bristles of squash vines; in 

 the stinging hairs of nettle; in stellate 

 hairs of hollyhock. (2) rotation, or 

 movement along the walls only, well seen 

 in the cells of many water plants, as 

 elodea, chara, and nitella (Fig. 387). 



387. Besides these and other move- 

 ments of protoplasm within the cell -wall, 

 there are also movements of naked proto- 

 plasm, of two main types: (1) amoeboid 

 or creeping movements, such as may be 

 seen in a plasmodium of myxomycetes, or 

 in an amoeba; (2) swimming by means 

 of cilia or flagella, illustrated in the 

 swarm -spores of water fungi, and of some 

 algae, and in motile bacteria. By the last 



type of movement the unicellular bodies 386. circulation of P ro- 



. \ toplasm in a cell of a 



(swarm-spores and bacteria) are often stamen hair of trad - 



times - 



moved very rapidly. To see movement 



in protoplasm, carefully mount in water 



a few hairs from the stamens of tradescantia (spider- wort). 



The water should not be too cold. Examine with a power 



high enough to see the granules of protoplasm. Make a 



sketch of several cells and their contents. It may be 



necessary to make several trials before success is attained 



