THE VITAL PROPERTIES OF THE CELL 



7:3 



circulate quite close together, sometimes in the same, sometimes in 

 opposite directions. The 

 nucleus, as well as the 

 chlorophyll and starch 

 grains, which lie embedded 

 in the protoplasm, are car- 

 ried slowly along by the 

 current. Similarly in this 

 case the most external hy- 

 aline layer of protoplasm, 

 which is in contact with 

 the cellulose membrane, is, 

 comparatively speaking, at 

 rest. In the second place, 

 the whole body of proto- 

 plasm itself slowly moves 

 along, in consequence of 

 which it changes its form. 

 Broad bands become nar- 

 rowed, and may after a 

 time disappear, delicate 

 threads increase in size, and 

 new processes are formed, 

 just as new pseudopodia 

 are protruded to the ex- 

 terior by Myxomycetes and 

 Rhi/opoda. Large masses 

 of protoplasm become 

 heaped up here and there 

 upon the layer lining the 

 cell-wall, whilst at other 

 places the coating becomes 

 thinner. 



c. Theories concerning Protoplasmic Movements. 

 Attempts have lately been made by various investigators, Quincke 

 ([II. 17), Biitschli (II. 7fl), Berthold (III. 2), and others, to com- 

 pare these protoplasmic movements with those exhibited by a 

 mixture of inorganic substances, and thus to explain them. 



Quincke has carefully investigated the movements which occur 

 at the areas of contact of various fluids. He placed in a glass 

 containing water a drop of a mixture of almond oil and chloroform, 



FIG. 41. A S, cells of a staminal hair of Tra- 

 descantia virginica. A Undisturbed streaming 

 movements of protoplasm. B Protoplasm which 

 has run together into ball-like masses in con- 

 sequence of irritation : a cell- wall, b transverse 

 wall of two cells ; c d protoplasm which has 

 massed itself together into small balls. (After 

 Kiihne ; from Verworn, Fig. 13.) 



