Hansen and von Staa believe that diseases invading internal organs frequently set in motion certain nervously excited reflexes, detection of which would aid in the recognition of the maladies initiating such reflexes. The signs are usually unilateral and are homolateral to the organs affected.
"Sympathetic anisocoria," the sympathetic difference in pupillary equality, is the point of origin for the investigation as reported by the authors in this volume. This pupillary enlargement, pointing a diagnostic finger to an ipsilateral organ disease, if it is accompanied by other unilateral reflex phenomena, may in their opinion offer valuable aid in indicating the affected organ.
A chapter is devoted to a historical introduction to the problem of reflex and algetic signs of disease. The importance of the observations of MacKenzie and Head is discussed. The work of Head is reviewed at some length. Head, it is noted, pointed out that diseases of certain organs