GENKRAL DISCISSION OF CROW ГЦ 



243 



turgor, and the effect of this stretching becomes subsequentl) established by 

 the deposition of new layers of cellulose. Traube's artificial cell is closely 

 analogous to the living cell in some respects. If a drop of gelatine is introdu« ed 

 into a tannin solution, a precipitation membrane of gelatine tannate i- formed 

 at the surface of the drop, and the cell thus artificially produced begins i<> 



5r 



Fig. 98. — Horizontal microscope. 



enlarge. This enlargement can be explained only by supposing that the gelatine 

 extracts water from the tannin solution; the outward pressure thus produced 

 causes a stretching of the membrane, which becomes ruptured at many places. 

 Through the small openings thus formed the gelatine once more comes into 

 contact with the tannin an<l the precipitation membrane i- reformed, when 

 the process is repeated. 



