The first public questioning of the validity of vivisection on medical grounds occurred in the 16th and 17th centuries. Notably, the Irish physician Edmund O’Meara who stated that ‘the miserable torture of vivisection places the body in an unnatural state’…wherein…’all the juices are brought to flow together’ thus contradicting the results of the experimentation. This is a primary example debating the effective course of scientific practice in an attempt to ensure that misleading results do not become common. O’Meara’s early anti-vivisection ideas would remain an important first step towards alternatives to animal experimentation.