PROTOPLASM. 



II 



corn, or the delicate staminal hairs of some plants, like those of 

 the common spiderwort, tradescantia, or of the tradescantias 

 grown for ornament in greenhouses and plant conservatories. 



Sometimes even in the living cells of the corn plant which we 

 have just studied, slow streaming or gliding movements of the 

 granules are seen along the strands of protoplasm where they 

 radiate from the nucleus. See note at close of this chapter. 



24. Movement of protoplasm in cells of the staminal hair of 

 " spiderwort." A cell of one of these hairs from a stamen of a 

 tradescantia grown in glass houses is shown in fig. 10. The 



Fig. 10. * 

 Cell from stamen hair of tradescantia showing movement of the protoplasm. 



nucleus is quite prominent, and its location in the cell varies con- 

 siderably in different cells and at different times. There is a 

 layer of protoplasm all around the nucleus, and from this the 

 strands of protoplasm extend outward to the wall layer. The 

 large spaces between the strands are, as we have found in other 

 cases, filled with the cell-sap. 



An entire stamen, or a portion of the stamen, having seveial hairs attached, 

 should be carefully mounted in water. Care should be taken that the room be 

 not cold, and if the weather is cold the water in which the preparation is 

 mounted should be warm. With these precautions there should be little diffi- 

 culty in observing the streaming movement. 



The movement is detected by observing the gliding of the 

 granules. These move down one of the strands from the nucleus 

 along the wall layer, and in towards the nucleus in another 

 strand. After a little the direction of the movement in any one 

 portion may be reversed. 



25. Cold retards the movement. While the protoplasm is 

 moving, if we rest the glass slip on a block of ice, the move- 

 ment will become slower, or will cease altogether. Then if we 



