The apparent displacement, or difference of position, of an object, as seen from two different stations, or points of view. In contemporary writing parallax can also be the same story, or a similar story from approximately the same time line, from one book told from a different perspective in another book.
In 1838, Theodor Schwann and Matthias Schleiden were enjoying after-dinner coffee and talking about their studies on cells. It has been suggested that when Schwann heard Schleiden describe plant cells with nuclei, he was struck by the similarity of these plant cells to cells he had observed in animal tissues.
In 1838 Schwann became familiar with Matthias Schleiden's microscopic research on plants. Schleiden described plant cells and proposed a cell theory which he was certain was the key to plant anatomy and growth. Pursuing this line of research on animal tissues, Schwann not only verified the existence of cells, but he traced the development of many adult tissues from early embryo stages.