HEALTHY, elderly people who are simply ''tired of living'' could be allowed to end their lives with a lethal injection under new euthanasia laws being debated by the Dutch parliament. MPs will discuss the proposals after campaigners collected more than 100,000 signatures in support. The influential Dutch ''Right to Die'' campaign, which has been active since 1973, has proposed training non-medical staff to administer a lethal injection to healthy people over the age of 70 who ''consider their lives complete''. Under the new ''vrijwillig levenseinde'', or ''of free will'', plans, the suicide assistants would be certified and would be required to make sure that patients were not temporarily depressed and had a ''heartfelt and enduring desire'' to die.