David photographed the crystallised chemical salicin, which comes from willow tree bark. Salicin forms the basis of the analgesic Aspirin – no doubt this is why some animals seek out willow bark to chew on.
David photographed the crystallised chemical salicin, which comes from willow tree bark. Salicin forms the basis of the analgesic Aspirin – no doubt this is why some animals seek out willow bark to chew on.