In the 19th century, physiological knowledge began to accumulate at a rapid rate, in particular with the 1838 appearance of the Cell theory of Matthias Schleiden and Theodor Schwann, that organisms are made up of units called cells.
Physiological knowledge began to accumulate at a rapid rate. This was in the 19th century. Organisms are made up of units cells. This was in particular with the 1838 appearance of the Cell theory of Matthias Schleiden and Theodor Schwann. Theodor Schwann was this. These units were called.