While migraine in later childhood differs in no respect from the disease as seen in the adult, its recognition in infancy and early childhood offers considerable difficulty, owing to the inability of the patient to describe symptoms accurately.
As is well known, migraine is often a hereditary disease, being directly inherited in about 50 per cent. of the cases. Not infrequently it has been known to occur in three or even four generations. It has not yet been ascertained whether or not the mendelian laws govern its inheritance. Like other hereditary diseases, it may be congenital, though this is exceptional. Such was the case with Russell's patient,1 who had the first manifestations at the age of 2 weeks, with attacks regularly thereafter every two weeks; at the age of 7 years the disease changed to the ophthalmoplegic type.
Age at Onset.—In Flatau's2 large series of 307 cases,