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vol. ^■ 



77/^ BEGINNINGS OF JLIFE. 



375 



contents.' He first obtained an insight into these 

 structures by observation of their production in the 



'rogyra. 



from large spores 



He 



'In the cells of these 



young 



Sfirogyra the existing spiral bands are often 



broken up, and from their substance are formed, in a 

 manner unknown to me, little cells in which a mem- 

 brane can be clearly detected surrounding green con- 

 tents. I call these cells, spore- mother-cells. They soon 

 increase in size, their membrane separating itself from 

 the contents and expanding into a large hollow vesicle. 



matter of ift The contents at the same time acquire a yellowish or 



yellow-brown colour, and separate into a central, denser, 

 yellow-brown nucleus, and a finely-granular mucilage, 



or Pringsb' which surrounds the nucleus and does fiot entirely fill 



the space between it and the membrane. 



ly 



granular mucilage then becomes balled together, in the 

 space between the yellow nucleus and the surrounding 

 membrane, into a single large corpuscle exhibiting a 

 sharply -defined outline, and appearing as a transparent 

 vesicle with finely- granular contents. The new cell 

 thus formed pushes the brown body, as the figures 

 show', out of its central position, against the wall of the 

 parent cell or the spore-mother-cell. The pressure of 

 these two bodies causes the rupture of the membrane of 

 the spore-mother-cell; the transparent cell emerges and 



bout independently and freely in the filament 

 cell in the manner of the zoospores/ They moved 



* Dr. Pringsheim's paper is illustrated by several figures. 



moves a 



I 



