This was during a time when xenotransplantation research was trending and in 1889 he injected himself under the skin with a combination of ground-up dog and guinea pig testicles. He theorised that the animal implants will help increases the hormonal effects to retard ageing. However his methods quickly lost favour when it was discovered any improvements were a result of the placebo effect. This real life scientist helped inspire Mikhail Bulgakov’s novel A Dog’s Heart (also known as Heart of a Dog).