The fact that the midline structures and the contralateral ventricle sometimes move toward the atrophic side in patients with asymmetric lesions of the brain is universally recognized. It is also recognized that such movement does not always take place. In the rather confusing literature on the subject there are references to meningeal adhesions, to shrinkage of cerebral tissue and to asymmetric growth as factors of importance.
In 1938 Casamajor and Laidlaw1 stressed the role of unequal growth. In the same year one of us (B. C.)2 suggested that, in children, asymmetric growth is of outstanding importance. In 1939 Robertson and Childe3 showed that adhesions could not explain the dislocation in many cases.
In this paper the results of a study of encephalograms of children are reported. All cases in the hospital files in which asymmetry was present were reviewed with particular reference to the mechanism which produces