The conscientious physician will never be satisfied with a diagnosis of headache. He knows that this condition is merely a symptomatic manifestation, and, strictly considered, never an independent disease. Careful inquiry and thorough investigation will disclose the fundamental disorder with certainty in many instances, and with probability in a further large number. In a small number the causative condition may be less apparent, or for a time may elude detection. As the diagnosis is the guide to treatment, the importance of recognizing the true state of affairs must be self-evident.
In our modern civilization there is, perhaps, no more potent single cause for headache than eye strain, and this may result from either refractive error or muscular imbalance. The recognition of this important fact is largely due to the intelligent observation, and its more or less general acceptance to the persistence of American physicians, and if it be wondered by