A worksheet function that is called by Excel can call back into Excel using the C API. An XLL command that is called by Excel can call the C API. DLL and XLL functions and commands that are called by VBA when VBA has itself been called by Excel can call the C API.
Cell Theory. The discovery of the cell was made possible by the invention of the microscope, which was made possible by improved lens-grinding techniques.Antoni van Leeuwenhoek (1632-1723), a Dutch tradesman, learned to grind lenses and assemble them into simple microscopes.nspired by Hooke's work, Leeuwenhoek began making microscopic examinations of his own. In 1678, he reported to the Royal Society that he had discovered little animals -- bacteria and protozoa -- in various samples. The society asked Hooke to confirm Leeuwenhoek's findings, and he did.
Robert Hooke is the scientist that is usually credited with the discovery of the cell. He was the first to use the word cell, because the first cells he observed looked similar to monkâs cells. He observed cork cells and published his findings in a book called Micrographia in 1665.round the same time as Robert Hooke, a Dutch scientist Antonie van Leeuwenhoek, also observed cells with his improved microscope. He is now known as âthe father of microbiologyâ and was the first to observe a live cell under a microscope.