Finally after countless attempts over many centuries the first successful human organ transplant occurred at a hospital in Boston in 1954. Dr. Murray was the surgeon behind the operation and his pivotal discovery permanently changed medicine. He performed a kidney transplant between two identical twins. Not only was this the first of many successful organ transplants but he helped improve immunological studies. The success of the operation depended mostly on the fact that since the donor and recipient were identical twins, they had identical blood and tissue types. Tissue typing for organs would be discovered because of this operation. Other physicians began researching into the immunological aspects of the surgery. Not too long after was the discovery and use of immunosuppressants in transplant surgery (PBS, 1998). Immunosuppressants are important as they weaken the patients immune system long enough to perform the operation and allow for the body to accept the new organ.