First Human Blood Transfusion Was from a Lamb (1667) — Why We Can't Use Animal Blood
The first blood transfusion (1667) used lamb blood — it worked only because the volume was tiny. Animal blood triggers catastrophic immune rejection in humans. Even genetically modified pig blood remains experimental.
Jean-Baptiste Denis, a French physician, performed the first documented blood transfusion to a human in 1667, transfusing lamb blood into a 15-year-old boy with a prolonged fever. The boy survived — considered a success at the time. Why it "worked": The volume transfused was small enough that the immune reaction was survivable. With larger volumes, the outcome would have been catastrophic. Why we can't use animal blood today (xenotransfusion): - Immunological rejection: the human immune system aggressively attacks foreign animal blood cells - Hemolysis: destruction of transfused red blood cells releases hemoglobin, potentially causing kidney failure - Hyperacute rejection can occur within minutes - Even with immune suppression, animal blood cells don't function correctly in human physiology (different oxygen-carrying characteristics, different cell shapes and lifespans) Modern research has explored genetically modified pig blood (pigs modified to remove surface antigens that trigger human immune response), but this remains experimental. The fundamental problem is that 200+ million years of evolutionary divergence between humans and other mammals created blood that is structurally and immunologically incompatible.