This research repeatedly confirms that the image quality of simple microscopes
is surprisingly high. During the research at Utrecht, one of the most exciting
images was obtained of an unmounted and unstained blood smear. The
erythrocytes themselves, shown in the picture as rounded discs, are clearly resolved.
Most interesting is the polymorphuclear granulocyrte (white cell) shown top, right of
centre. Its lobed nucleus (visible in a selective enlargement) can be discerned,
a remarkable result for a single lensed microscope of the late seventeenth century.