R v Roulston - [1976] 2 NZLR 644

Criminal law — Homicide — Murder — Accused under influence of drug — Evidence and proof — Defence of insanity must show probable evidence of disease of mind — Burden of proof lies on Crown to prove every essential element but may rely on presumption that every man has sufficient mental responsibility for his crimes — Judicial discretion to comment on accused's failure to give evidence — Address by prosecution — What is permissible or impermissible.