The cover of Australian Prescriber features the Eye of Horus. Horus, an Egyptian god, had his eyes torn out in a dispute. Each piece of the eye symbol represents a fraction. These pieces were used to specify the quantities of different ingredients in a prescription.
The complete symbol may have evolved into the prescribing sign which is still used today.
However, Richard Worrell, one of our Sydney readers, believes the prescribing sign evolved from the Roman astrologers' symbol for the planet Jupiter. By writing the symbol on each prescription, the ancient physicians were calling on Jupiter to influence their treatment. Modern physicians need look no further than an issue of Australian Prescriber for a good influence on their prescribing.