Arnold Lande, a retired American heart and lung surgeon, has patented a scuba suit that would allow a human to breathe “liquid air”, a special solution that has been highly enriched with oxygen molecules. The idea immediately conjures up the terrifying spectre of drowning but our lungs are more than capable of taking oxygen from a solution. “The first trick you would have to learn is overcoming the gag reflex,” explains Lande, a 79-year-old inventor from St Louis, Missouri. “But once that oxygenated liquid is inside your lungs it would feel just like breathing air.”