It is necessary to adhere to a uniform time of death. To determine this, the normatively relevant concept of death and the criteria for establishing death in terms of medical proof must be distinguished. The notion of death, which must be determined as a matter of first priority, is not something which is medically predetermined but is a normative convention. According to the legal view prevailling today, this does not depend on complete cessation of biological activities, or on the cessation of heart and breathing activity, but solely on brain death, i.e. (to quote from pertinent commentary of the scientific advisory board of the Federal Chamber of Physicians), on the "complete and irreversible collapse of the overall function of the brain with a circulatory function which can still be maintained in the rest of the body." Brain death is characterized by the irreversible loss of cerebral and brainstem function. Death of the patient is the extreme boundary of therapeutic activity which the physician may not transgress. Irreversible and total loss of function of the brain thus justifies the doctor in discontinuing his measures and indeed compels him to do so. The physician should preserve life and help the dying patient, but should not prolong death. Even before the extreme limit of brain death, intensive therapy may no longer be indicated, so that the physician is not obliged to make further efforts to prolong life.