PATHOANATOMIC OBSERVATIONS
Collins3 was the first to report pathologic observations on the disease; the previous observations had been solely ophthalmoscopic, the authors depicting the characteristic features—the enormous dilatation, the tortuosity and change in color of the vessels, and even the subsequent exudative changes—but failing to visualize the true nature of the process, the tumor formation within the retina, and concluding that the visible nodule with the two feeding vessels represented an aneurysm. Clinically, the aneurysmal nature of the nodule was questioned by the circumstance that pressure on the bulbus elicited pulsation of the vessels but that neither pulsation nor bleeding of the nodule accompanied the pressure. According to von Hippel, this lack of pulsation is evidence against the aneurysmal connection between artery and vein, and the possibility that the pulsation is concealed by the coagulation products present seems to lack factual confirmation. Other authors, such as Jacoby, emphasized that