lp5a The beginning of the membrane-pump concept

"Ideas of Life and Matter: Studies in the History of General Physiology 600 BC to 1900 AD, University of Chicago Press, Chicago 1969, Volume 2, p. 194, by Thomas Hall .The following is quoted from Chapter 41, "The Cell after Schwann". Theordor Schwann (1810-1882) was the major founder of the "Cell Theory".

"Absolutely fundamental to Schwann's conception was this belief that the containing membrane---of cell or nucleus---was prior in importance to its contents. The content of the cellular cavity , i.e., of the inter-space (Zwischenraum) between the nuclear and cellular membranes, was typically, for Schwann, a homogeneous, transparent liquid.

In his view, the control of the cell's activities, insofar as these were interpreted by him, was localized in its membranes, especially the outer membrane. ...The membrane possesses a "plastic power"...And there is (also) a "metablic power" , Schwann said, by which the membrane chemically alters the fluid substances adjacent to it---the Zwischenkeimstoff outside and the cell content (Inhalt) within..."