“cells originate not only from cells but also from living substance that does not have the structure of the cell.” LifeCells Book:The Origin of Cells Source: The Origin of Cells
“there is a countless number of the simplest formations, viruses, which evidently stand on the border-line between the living and the non-living.” LifeCellsInorganic To Organic Book:The Origin of Cells Source: The Origin of Cells