Trypsin digestion of the retina has been advantageously employed to study the morphology of retinal vessels in flat mounts.1These two-dimensional observations, however, are inadequate for the study of the relationships of the vessels, particularly of the capillaries, to each other at various depths in the retina. It is our purpose in this communication, therefore, to report experience with preparation of trypsin-digested retinas examined in three dimensions. The retinas were first treated with trypsin as previously described.1After incubation the isolated vessels were returned to 10% formalin for 10 or more hours, and then stained either by brief immersion in methylene blue or Paragon solution or by adding a few drops of the dye to an aqueous solution in which the vessels were suspended. The vessels were examined with a dissecting microscope (magnification 2080 ×) while suspended in a water medium or after they had been embedded in