Relax your eyes until you see a fourth image appear. Depending on whether  you  cross or separate your eyes, one of the two images in the middle will be the correct 3D image and the other middle image will be the opposite direction 3D.

Pathology
 Bone from rat recipient of limb transplant, undergoing lethal graft-versus-host disease. Approx. 40µ thick. Plan Apochromat 20x. 3D perspective reveals fibrous matrix bone spicule and bone canal with infiltrating mononuclear cells. (Charles W. Hewitt, Ph.D., UMDNJ - Robert Wood Johnson Medical School.)

3D Transmitted Light
  Thick skin biopsy, (40µ thick) viewed with Multiple Oblique™ illumination, a transmitted light technique and utilizing the image enhancement iris. Mag. 125x.