CHEMICAL PHENOMENA IN LIFE 



of benzene in the contrary direction. An osmotic 

 pressure must be produced, therefore, in the 

 system on the side of the benzene. When the ex- 

 periment is carried out animal membrane saturated 

 with water is placed, instead of a layer of liquid 

 water, between the ether and the benzene. The 

 benzene is poured into a glass funnel connected 

 with a glass tube, and the funnel is closed with the 

 saturated membrane. Then the funnel is dipped 

 into a vessel containing ether. After a certain 

 time the liquid rising in the glass tube shows the 

 endosmotic streaming in of ether, subsequently the 

 osmotic pressure. 



In the foregoing description the term Plasmatic 

 Membrane has often been employed for the super- 

 ficial layer of hyaloplasm. We have to justify the 

 choice of this expression. Membranes are films of 

 firmer consistence than the material, viz. the 

 liquid upon the surface of which they are formed. 

 So the expression plasmatic membrane implies a 

 firmer consistence for this layer than for the 

 hyaloplasm itself. We know from daily experience 

 that a colloidarsolution such as a solution of albu- 

 min or starch paste, is inclined to form a thin film 

 on the surface, which has almost the physical con- 

 dition of a solid substance. Protoplasm, being a 

 colloidal system, will most probably not differ from 

 other colloids in this respect. We notice, indeed, 

 after a lesion 'of a'cell when the cell and its proto- 

 plasm have been cut through, that the surface of the 

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