Saltire detected the symbol, which often appears with balls in the quadrants formed by the arms of the chi-cross, in standards that appear on the coins of Persepolis. She suggested that early Christians endorsed its solar symbolism as appropriate to Christ. She also wrote: "although it cannot be proved, ... in the white saltire of St. Andrew we still have a reminiscence of the old standard of the Persepolitan kingdom". In the old European Union standard, a black saltire set in an orange square is the hazard symbol for irritants (Xi) or harmful chemicals (Xn). It indicates a hazard less severe
Caduceus as a symbol of medicine when few people understand the visual signs with which he was so familiar." In support of the idea that the caduceus had a long-standing association with medicine, Garrison also mentioned the fact that the English medical printer Churchill used the symbol as a printer's device, beginning some time around 1844. Friedlander has examined this subject in detail, and shows that Churchill was well aware that the rod of Asclepius was the accepted symbol of medicine. He is, it seems, inclined to think that the adoption of the caduceus in this context probably had something to do with the relation between