The so-called nervous complications of whooping cough are well recognized; they generally have been attributed to asphyxia, cerebral edema or congestion, brain injury from hemorrhage, encephalitis or meningitis. The symptomatology of these various forms of injury is, of course, manifold, but the outstanding symptom and the one usually present and common to all is convulsions. As a matter of fact, however, the rarity with which definite pathologic lesions are proved to exist is in rather striking contrast to the frequency with which convulsions occur. Indeed, it would seem quite probable that the existence of convulsions in whooping cough has frequently been the principal basis on which a diagnosis of cerebral hemorrhage, encephalitis or other lesion, has been set up. It is the purpose of this paper to call attention to the fact that infantile tetany, and not anatomic injuries or an unknown toxin, is often the cause of the convulsions