By making use of the newly invented achromatic microscope, Ehrenberg was able to see Euglena's eyespot, which he correctly identified as a "rudimentary eye" (although he reasoned, wrongly, that this meant the creature also had a nervous system).
Utilizando o microscopio acromático acabado de inventar, Ehrenberg puido ver a mancha ocular ou estigma de Euglena, que identificou correctamente como un "ollo rudimentario" (aínda que razoou erradamente que iso significaba que a criatura tiña tamén un sistema nervioso).