Carl Frederick Tessmer was born in North Braddock, Pennsylvania on May 28, 1912. He received his higher education at the University of Pittsburgh, Pittsburgh, Pennsylvania. In 1933 he received his Bachelor of Science with highest honor. From 1933 to 1935, he studied medicine at the University of Pittsburgh Medical School and graduated in 1935 with a Doctor of Medicine degree. Dr. Tessmer completed a rotating internship at the University of Pittsburgh Medical Center, 1936. He served his residency in pathology at Presbyterian Hospital, Pittsburgh Pennsylvania, 1937. In 1937, he was granted a one year fellowship in pathology, Mayo Clinic in Rochester, Minnesota. On August 21, 1939 he married Maxine Keller. Together they had two sons, Jon and David. Upon the completion of his fellowship Dr. Tessmer accepted a residency in pathology at Queens Hospital in Honolulu, Hawaii, 1939-1940.

Dr. Tessmer has had a twenty-three year association with the United States Armed Forces. He served in the United States Army Medical Corps, from 1940-1963 and retired with the rank of Colonel.

During the early 1940s he worked in Laboratory Services in hospitals in Hawaii and Saipan. In 1946, he traveled back to the mainland and the East coast. At the Army Institute of Pathology in Washington, D.C. he served as a pathologist. He also was part of Operation Crossroads with Task Force One on Bikini Island, 1946 and worked for the Naval Medical Research Institute, Bethesda, Maryland, 1947.

In 1948, Dr. Tessmer was appointed the first Director of the Atomic Bomb Casualty Commission. Dr. Tessmer's association with the program began even before its formal inception, he took part in a survey in 1946 which actually established much of the basis for the organization. This was with a distinguished pathologist Dr. Shields Warren, Professor of Pathology, Harvard Medical School, and this included a significant amount of clinical data on A-bomb survivors, photographs and blood smears. As matters subsequently developed, he came the director of the program in Japan under the auspices of the National Academy of Sciences-National Research Council and Atomic Energy Commission.

The Tessmer family returned to the United States in 1951. For the next three years, 1951-1954, Dr. Tessmer was the Commanding Officer for the Army Medical Research Laboratory in Fort Knox, Kentucky. After attending the Basic Radioisotopes Training Course at the Oak Ridge Institute of Nuclear Studies in 1954 he was appointed Chief of the Radiation Pathology Branch and Chief of the Basic Science Division for the Armed Forces Institute of Pathology, Washington, D.C. He served as Chief for six years, 1954-1960. Dr. Tessmer returned to Japan in 1960. For the next two years, 1960-1962, he served as the Chief to the Medical General Laboratory (406). Dr. Tessmer travelled to Houston, Texas after a year with the Walter Reed Army Institute of Research in Washington, D.C., 1962-1963.

Dr. Tessmer has been affliated with the University of Texas for over a decade, 1963-1974. He has served as Chief Pathologist and Professor of Pathology at the University of Texas M.D. Anderson Hospital and Tumor Institute at Houston and Graduate Faculty member at the University of Texas Graduate School of Biomedical Science at Houston. While teaching at UTGSBS he sponsored four graduate students for the doctoral degree. From 1971-1973 he was the Program Coordinator for the University of Texas Medical School at Houston.

From 1973-1985, Dr. Tessmer was associated with the Olin E. Teague Veterans' Center, Temple, Texas in several capacities. His appointments were: Chief, Laboratory Service of the Olin E. Teague Veterans' Center, 1973-1985; Medical Director, Medical Technologist School, Southwest Texas University, 1976-1977; Medical Director, Medical Technician School, Temple Junior College, 1973-1985. Dr. Tessmer's last academic post was as Professor, Department of Human Pathology and Laboratory Medicine, Texas A&M University College of Medicine, College Station, Texas, 1977-1985.

Dr. Tessmer was very active as a physician, pathologist, adminstrator and professor. He had medical licensure in the states of Pennsylvania, Minnesota, Hawaii, and Texas. He wrote forty-five publications. and was a member or fellow of eleven professional organizations. They were: American Society of Clinical Pathologists (Fellow), College of American Pathologists (Fellow), American Association of Pathologists, Radiation Research Society, Washington Society of Pathologists (President, 1959-1960), International Academy of Pathologists, Texas Medical Association, Texas Society of Pathologists, Texas Society for Electron Microscopy, Member, CAP House of Delegates, Texas, 1971-, Sigma Xi. His expertise has been in high demand. He served as a consultant to a number of institutes, committees and agencies. They were: Oak Ridge Institute of Nuclear Studies, Medical Division, 1956, the Walter Reed Army Institute of Research, Division of Biology and Medicine Advisory Panel, AEC (Californium 252 program), 1968, HEW, Food and Drug Admistration, Radiation Bio-Effects and Epidemiology Advisory Committee, 1972. Dr. Tessmer has had a number of appointments: Diplomate to the American Board of Pathology - Clinical and Anatomic Pathology, 1941, Subcommission on Radiation Pathology, I.C.P.R., 1967-1973, President of the Houston Society of Clinical Pathologists, 1970-1973, Member of the International Commission for Stage Grouping on Cancer and Presentation of Results (I.C.P.R.) (International Society of Radiology), 1973-.

Dr. Tessmer retired from academia in 1985. His sons - Jon F. is a physician in Brownwood, Texas and David P. Lives in Pittsburgh, PA. On October 13, 1992 he married Shizue Murata. They enjoyed living in the Texas countryside and traveling until Dr. Tessmer's death on February 2, 2012.