There are differences of opinion about the pathogenesis of Perthes' disease. All are agreed that it is due to ischaemia, but the cause of this and the size and number of infarctions are in dispute. Through the generosity of the contributors six whole femoral heads and core biopsies of five other cases have been studied radiographically and histologically. The findings ranged from an ischaemic arrest of ossification in the capital articular cartilage without infarction to multiple complete infarctions of the epiphysial bone. The ensuing reparative process contributes to the pathology, which is of a range to warrant grading or grouping.

A histopathological study was made of the hip joints from two children with Perthes' disease who died from unrelated causes. These cases illustrate the variability of three aspects of morphology: the extent and number of infarctions, of trabecular fractures and of the reparative process. 276 THE JOURNAL OF BONE AND JOINT SURGERY

IN this paper I desire to describe a method of performing a radical operation for the cure of inguinal hernia which I have now been employing for nearly eighteen months, and which has so far given results that are quite satisfactory.