A versatile incident illuminator for intravital microscopy.

A simple incident illuminator (epiilluminator) for intravital microscopy using a mirror with 50% reflectance and 50% transmittance, placed at 45 degrees to the optical axis of the microscope, in combination with a polarizer and analyzer is described. Such a system can easily be mounted in a Ploemopak incident illuminator as used for fluorescence microscopy. Images of the red blood cells contained in the microvessels appear as dark on a light background. With the use of the system, microscopic images of good quality could be obtained from human skin capillaries, and skin, pial and intestinal microvessels in rats. In muscle, however, only the superficial capillaries could be adequately visualized.