20 



HUTCHINSON'S POPULAR BOTANY 



FIG. 37. TRAVELLERS' JOY (Clematis vitalba). 

 Young cells from the Stem, with walls of cellulose. 



This loads us to another im- 

 portant phenomenon in cell-building 

 the conversion of lifeless into 

 living matter. Deeply interesting 

 is the power which the protoplasm 

 possesses, not only of building up 

 formed material from itself, but of 

 transforming the lifeless material 

 which it draws to itself into living 

 matter ! There is nothing in the 

 whole range of Nature more wonder- 

 ful. A tiny speck of matter viscid, 



'* < $^%Z'^^^^J0' "S^Y transparent, and, so far as the 



]^- xfT jlj highest powers of the microscope 



I III Vw xi\ Can i n f rm ns ' structureless is able 



JJA xXV JK^ss_-^'^ to produce matter like itself living, 



formative matter out of the non- 

 living material by which it is sur- 

 rounded ! Yet the two are quite 



distinct. The difference between the minute speck of protoplasm and that 

 which nourishes it is absolute. Nor does the one pass by delicate gradations 

 into the other. The change from the non-living to the living is instantaneous. 

 No less absolute is the distinction which exists between living matter and 

 the formed cellular material which is produced by it. The passage from 

 one state into the other is sudden and abrupt : matter cannot be said to 

 half live or half die. Thus a ceaseless round of change goes on an endless 

 transformation of the lifeless and inorganic into the living but structureless, 

 and of the latter into formed material. 



The wonderful movements of protoplasm have been often observed, 

 and perhaps no plant has been more studied for this purpose than the 

 Common Spiderwort or Flower-of-a-Day (Tradescantia virginica). If we 

 remove a single hair from a stamen of this plant by tearing off a portion 

 of the cuticle to which it is attached (thus avoiding injury to the hair 

 itself), and place the object in a drop of water under the microscope, we 

 may watch for ourselves two of the most characteristic movements of 

 protoplasm. Presuming that we have been fortunate in a choice of speci- 

 men, we shall find that the hair consists of three or four cells, of which 

 the shortest and broadest is at the base (fig. 34). In this cell the proto- 

 plasm will shortly be seen to be moving in several elliptical currents from a 

 common point, the nucleus ; while in the other cells it will be seen to 

 travel round the cell-walls, though the nuclei, as before, will be the 

 points of departure and return. The former kind of movement is known 

 as circulation, the latter as rotation. 



Rotary movement may also be well seen in certain cells of the AVater- 



