ADYNAMIA EPISODICA HEREDITARIA 123 appeared in II 6, whose parents, sibs and many older relatives were known to have been unaffected. There have been no consanguineous marriages. At first sight it would appear that the inheritance is dominant and therefore similar to that described by Gamstorp et al. and that occurring in paramyotonia congenita, since of the 34 children born to affected parents, 17 were known to be abnormal. The inheritance, however, would seem to be very different in affected males and females for only one out of 11 children born to 3 affected males was abnormal,• whereas 16 of the 22 children born to 5 affected females and surviving beyond infancy were abnormal. This difference between the offspring of affected males and females is statistically significant (P< 001), as also is the difference between the observed inheritance in the affected males and that expected were the mode of transmission dominant< P< 0-02).

In other respects the condition behaves as a dominant, all affected children having an abnormal parent and all the unaffected having normal children. It may be of interest, however, that 2 cases of paralysis of unrelated type have occurred in the family. From the history it would appear that III 1 who was almost completely and permanently paralysed from birth was a case of congenital diplegia, but the diagnosis of IV 15 is more uncertain. He had severe and permanent paralysis of the lower limbs from birth and died of pneumonia aged 8.