GREEN SHOOTS: Matthias Schleiden was not satisfied merely with classifying plants; instead, he studied them under his microscope. Those observations prompted Schleiden to theorize about the importance of cells and their nuclei. This picture shows Schleiden’s sketches of an assortment of cells and embryonic structures from a palm, an orchid, the cherry rice-flower, and several other plants.WELLCOME LIBRARY, LONDONIn 1837, Matthias Schleiden and Theodor Schwann were dining together in Berlin when Schleiden mentioned a recent discovery by the Scottish botanist Robert Brown: the nucleus. Brown had shown that it was present in a variety of plant cells.
Schwann, an animal physiologist, and Schleiden, a botanist, were students of Johannes Peter Müller at Berlin’s Humboldt University. When Schwann heard about the nucleus, he realized that he had seen a similar structure in the vertebrate notochord—a rodlike structure in the embryo that develops into the spinal column. Sure enough, when the duo got together to examine notochords under the microscope, they saw cells containing nuclei just like those seen in plants. Such observations might seem ho-hum today, but they were unprecedented at the time.
Robert Hooke had coined the word “cell”—short for cellula, or “small compartment” in Latin—in the mid-17th century, after he’d seen tiny rectangular shapes while studying slices of cork using a rudimentary microscope. But Hooke had not grasped the importance and ...
