Hartmann completed his residency in
pediatrics at
St. Louis Children's Hospital in 1923. He was an instructor in pediatrics at
Washington University School of Medicine and was promoted to assistant professor in 1925 then associate professor in 1927. He was promoted to a full professor in pediatrics and head of the pediatric department at Washington University in 1936. His scientific work pertained to
biochemistry and problems of
metabolism, while his clinical pediatric interests included
anoxia,
hypoglycemia,
nephritis,
nephrosis and
chemotherapy. He was among the first doctors to use
insulin to treat
diabetes in infants. His best known contribution to medicine was in body
electrolytes and
intravenous fluids replacement. He modified
Ringer's solution by adding
sodium lactate, an alkaline substance, to treat
acidosis in children. His invention,
Ringer's lactate solution, became popular internationally and is commonly known as Hartmann's solution. == Personal life ==