George Johnston was a Berwickshire based naturalist and physician. He founded the Berwickshire Naturalist Club and was instrumental in the foundation of the Ray Society. Margaret Gatty began corresponding with Johnston in 1850 and they kept in regular touch until his death in 1855. He often recommended the benefits of pain relief medication to Margaret, who was regularly incapacitated by illness. It is believed that he recommended the use of chloroform during childbirth to Margaret, who thus became the first woman in Sheffield to benefit from its use.
Johnston wrote many books on natural history, described several new species to science and has many species named after him. The naturalist Charles Henry Gosse once stated that Johnston should be described as the father of British marine invertebrate zoology.