Charles Darwin Quote

After a time the minute colourless particles which are imbedded in the flowing protoplasm are drawn towards and unite with the aggregated masses; so that the protoplasm on the walls being now rendered quite transparent is no longer visible, though some is still present, and still flows, as may be inferred from the occasional transport of particles in the cell-sap.

"The action of carbonate of ammonia on chlorophyll-bodies" Journal of the Linnean Society of London (Botany) (read 6 March 1882) volume 19, pages 262-284, at page 262