Murdoch studied pharmacology, married and in 1954 moved to Timaru to set up a pharmacy. Small town life meant that his knowledge and expertise were also in demand as a vet, and his work treating animals led to many of his inventions. The glass syringes that were used at that time were sterilised between uses, but not always properly. Often the diseases spread by improperly sterilised syringes were worse than the ones they were meant to be curing.
Murdoch's idea was simple, and changed everything. Flying on a DC3 one day, Murdoch had a 'eureka moment' and pulled out the fountain pen he always travelled with. He designed a disposable plastic syringe, and patented it in 1956 at the age of 27.
He set about making dies and took a prototype to the New Zealand Health Department to get their blessing and help with its development. They gave him the feedback that his idea was good, but 'too futuristic'. In their opinion, nobody would want to be injected from a plastic syringe.