The Respirator Brain

To the Editor.— The letter by Dr Adams on the "respirator brain" and the reply by Dr Walker in the August issue of theArchives(33:589, 1976) indicates the degree to which this subject is plagued by conceptual difficulties. Dr Adams implicates autolytic changes occurring postmortem in the sense of occurring after brain death, while Dr Walker continues to affirm that agonal or premortem events are involved, at least in part. The word autolysis means self-dissolution, implying indigenous changes not related to continued blood flow and the influence of hematogenous cells or enzymes. It is an extension of the literal meaning of the word to imply that autolysis is not "vital," that it must of necessity be postmortem. Those of us who believe that most macrophages observed in cerebral infarcts are indigenous in origin could view the evolution of such infarcts as being partially autolytic, even when occurring many years