83 



LECTURE VI. 



inner side of the cell-wall, and is very watery, therefore resembling a fluid, and 

 moves as a flowing stream along the cell-wall, while with it float the nucleus and 

 the chlorophyll corpuscles, and incidentally small crystals of calcium oxalate. This 

 form of movement has been distinguished as rotation of the protoplasm from that 

 first described, which is termed circulation. 



Circulation and Rotation, however, are only special forms of the movements 

 of protoplasm within closed cells. If cells rich in protoplaspi, especially those 

 of the Ceeloblastic Algse, are ruptured under the microscope, the protoplasm 

 gushes forth out of the opened cell-membrane as a viscid mass, which may 

 assume the most various forms : these are by no means simply those of a viscous 

 fluid body, but are produced by peculiar movements within the protoplasm. An 



example of this is illustrated in Fig. 78. Here 

 may be noted the remarkable fact that sepa- 

 rated portions of the exuded protoplasm, provided 

 they contain one or more nuclei, may become 

 surrounded after some timfe with a cell-mem- 

 brane, grow, and form a new plant. Such is the 

 case not only with the Vaucheria represented in 

 the figure, but, according to Schmitz, also with 

 some other, non-cellular Algse {Siphonocladiun 

 and Vallonia). What happens in such cases by 

 means of external accidental influences, is con- 

 stant in the reproduction of very many Algse. 

 Either the whole mass of protoplasm of their 

 cells becomes loosened from the surrounding 

 wall, and emerges through an aperture in the 

 latter ; or the protoplasmic body is first broken 

 up into a large number of individual nucleated 

 portions, which are then expelled from the 

 parent cell-membrane. Such free protoplasmic 

 bodies — the swarm-spores of the Algse — are 

 furnished with more or less fine cilia, by the 

 aid of which they swim about in water, just 

 like Infusoria, until they become fixed in some place, surround themselves with a 

 cell-membrane, and begin to grow. The movement of such protoplasmic bodies, 

 which are generally ovoid in shape, is two-fold;- they revolve round the axis, 

 and at the same time travel forward in the water, a motion similar to that of a 

 planet in space, or of a shot fired from a rifled cannon. 



To the most remarkable phenomena in the life of protoplasm belong the 

 processes observed in a subdivision of the Fungi, the Myxomyceies. During 

 their vegetative condition, before they develope their spores, these organisms 

 consist entirely of naked protoplasm (i.e. not surrounded with a cell-membrane) 

 which occasionally creeps forth in large quantities out of the nourishing sub- 

 stratum of foliage or tan on to the surface, and is found for hours in 

 active movement from place to place as a so-called plasmodium. This 

 phenomenon is easily observed in the so-called 'flowers of tan.' On moist, 



Fig, 79, — C swarm-spore oi Qldogoniiiim, free and 

 motile ; D the same after it has becopie fixed and has 

 formed the organ of attaciiment; E exit of all the 

 protoplasm of a germinating- plant in the form of a 

 swairm-spore. {X 350. After Pringsheim, ^ahrh. f. 

 iviss. Bot. I. Taf. i.) 



