Back to Featured Projects Seeing Cells Exhibit Overview Seeing Cells in Life Theory of Cells as Basic Units of Life Protoplasm as the Living Stuff Cell Specialization From Fertilization to Organisms Presenting and Representing "The" Cell Experimental Manipulations Resolving the Inside of Cells Inside Living Cells Seeing How Cell Parts Move Seeing Cell Aggregates Designing Synthetic Cells Imagining Cells Seeing Cells Videos Home Groundbreaking Research at the MBL Research Centers Eugene Bell Center Featured Projects Seeing Cells Exhibit Experimental Manipulations In the 1890s, German biologist Wilhelm Roux argued that just observing what happens in nature is not enough to understand life. Biological research must become experimental. The MBL community took up this call. Download Experimental Manipulations In order to understand the role of cells in regeneration, for example, Thomas Hunt Morgan experimented with planarians and hydras, cutting them into bits and observing what happened next. HoverTouch to magnify Regeneration of planaria Morgan 18991 MBL Rare Books Collection As whole organisms regenerated from the pieces, he asked whether the remaining cells had been transformed to take up different functions, or whether new cells had filled the void. He urged others to join him in testing interpretations. HoverTouch to magnify Regeneration of hydra Morgan 18992 MBL Rare Books Collection Jacques Loeb took up the call and experimented with sea urchin egg cells by placing them in different concentrations of salt water. In the right conditions, egg cells began to divide, even without fertilization by sperm, a process called parthenogenesis. HoverTouch to magnify Organisms developed from unfertilized eggs Loeb 19003 MBL Rare Books Collection HoverTouch to magnify Cells dividing without fertilization Loeb 19004 MBL Rare Books Collection Loeb also asked how he could manipulate environmental conditions, both inside and outside organisms, to learn how they affect cells and their functions. As experimental biologists asked new questions, using the new methods, they generated observations that raised more questions. In particular: what is going on inside cells? Previous Panel Next panel Download Experimental Manipulations Morgan, Thomas Hunt. Regeneration. New York: The Macmillan Company, 1901. Page 50, Figure 24. Morgan, Thomas Hunt. Regeneration. New York: The Macmillan Company, 1901. Page 163, Figure 47. Loeb, Jacques. Artificial Parthenogenesis and Fertilization. Chicago: The University of Chicago Press, 1913. Page 76, Figures 27-31. Loeb, Jacques. Artificial Parthenogenesis and Fertilization. Chicago: The University of Chicago Press, 1913. Page 292, Figures 78 and 79.