MOVEMENTS OF PROTOPLASM. 



8i 



large cells, considerable quantities of protoplasm, usually so distributed that 

 a thicker or thinner layer of it clothes the inner side of the cell-wall, while a 

 more or less massive clump envelopes the nucleus, from which threads or bands 

 of protoplasm pass out to the wall. This arrangement of the protoplasm is very 

 easily seen under the microscope, without disturbance to its life, in the hairs on 

 the epidermis of many plants. If we observe such a living cell attentively 

 and for a long time, the substance of the protoplasm is seen to be in con- 

 tinual movement — one of the most remarkable of phenomena, which allows of the 



FIG. iS.—B to G protoplasm from a ruptured filament of faiicherza terrestris, slowly emerging in water, and m various 

 successive conditions, at intervals of about five minutes, h cell-membrane of the ruptured filament ; ;' the portion of protoplasm 

 still in the filament ; a (in A", C, D, F) a sphere of protoplasm becoming detached, forming vacuoles, and then becoming 

 deliquescent (in F) ; If a branch of the protoplasm from which the mass d' separates otf. This is isolated in D, and then 

 becomes deliquescent in F; c and c' behave similarly. G shows the further changes of the portion c" in F ; j4 a recently 

 escaped clump' of protoplasm, rounded off into a sphere, the chlorophyll granules lying all together inside, and hyaline 

 protoplasm enveloping the whole as a skin. 



immediate recognition of the internal disturbances of equilibrium taking place in the 

 protoplasm. These movements are rendered visible by means of the finer or 

 coarser granules distributed in the protoplasm. These are seen to travel from 

 the cell-wall in the strands of protoplasm towards the nucleus, returning thence by 

 the same or other strands to the peripheral layer; and here gliding onwards 

 again, sooner or later to be carried once more through other threads of proto- 

 plasm to the nucleus, and thence to turn back as before. In many water-plants 

 the movement of the protoplasm is simpler : it forms a relati\-el\- thick layer on the 

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