Fernando E . Rodríguez Vargas Major Fernando E . Rodríguez Vargas , DDS ( February 24 , 1888 – October 21 , 1932 ) was an odontologist ( dentist ) , scientist and a Major in the U . S . Army who discovered the bacteria which causes dental caries . Early years . Fernando Emilio Rodríguez Vargas was born in Adjuntas , Puerto Rico to Luciano Rodriguez and Dolores Vargas . There he received both his primary education . Adjuntas did not have a high school until 1950 , therefore he attended high school in the City of Ponce where the other students from Adjuntas went . After he graduated from high school , he applied and was accepted in the University of Puerto Rico where he took paramedic courses and earned his teachers certificate . He then went to work as a United States Internal Revenue Service inspector and later as a Spanish translator for the United States War Department . In 1910 , Rodríguez Vargas applied and attended Georgetown University , in Washington , D . C . where he earned his DDS degree in 1913 . From 1913 to 1915 , Rodríguez Vargas had his private practice in Washington , D . C . In 1915 , he joined the United States Indian Medical Services , and was assigned to Tucson , Arizona located in the southwest region of the United States . During this time he studied the mottled enamel situation which was affecting Native Americans . Military service . On August 16 , 1917 , he joined the United States Army and on September 14 , he was commissioned a First Lieutenant . Rodríguez Vargas was assigned to the Army Dental Reserve Corps and attended a course at the Medical Officer ' s Training Camp at Camp Greenleaf , Georgia before being sent overseas . The U . S . Congress had already declared war on Germany when Rodríguez Vargas was sent to the United Kingdom . On August 1919 , he was reassigned to San Juan , Puerto Rico and served in Camp Las Casas . During his service in Puerto Rico he met and married Maria Anita Padilla . Rodríguez Vargas , who promoted to Captain on September 8 , and his wife had a son which they named Roberto . Scientific work . On February 18 , 1921 , Rodriguez Vargas was sent to Washington , D . C . and assigned to the Army Dental Corps where he continued his investigations in the field of bacteriology . Rodríguez Vargas was there as an educator and investigator of the bacteriological aspects of dental diseases . His research led him to discover the bacteria which causes dental caries . According to his investigations , three types of the Lactobacillus species , during the process of fermentation , are the causes of cavities . In December 1922 , he published an original and fundamental work on the specific bacteriology of dental caries . His findings were published in the December issue of the " Military Dental Journal " titled " The Specific Study of the Bacteriology of Dental Cavities " . Rodríguez Vargas also developed the techniques and methods of analysis . On September 28 , 1928 , Rodriguez Vargas published in the " Journal of the American Medical Association " his findings in the effectiveness of Iodine and other chemical agents as disinfectants of the mucous membranes of the mouth . Since then , other scientists have used the findings of his investigations as the basis in the study of the bacteriology of dental caries . Rodríguez Vargas earned a Bachelor of Science degree from Georgetown University , in 1924 where he was an Associate Professor of Bacteriology in the Ental School . On September 14 , 1929 , he was promoted to the rank of Major . Later years . Rodríguez Vargas was a member of the District of Columbia Dental Society , the International Association of Dental Research and a fellow of the American College of Dentists . In 1925 , he was assigned to the General Dispensary , U . S . Army in Boston , Massachusetts until August 1926 , when he was reassigned to Holabird Quartermaster Depot , Baltimore , Maryland , which would turn out to be his last assignment . Major Fernando E . Rodríguez Vargas became ill with pneumonia and was hospitalized at the Walter Reed Hospital for treatment . On October 21 , 1932 , Rodríguez Vargas died of complications at the age of 44 . He was buried at Arlington National Cemetery in Section 6 Site 8429 . He was survived by his widow and son . Honors . On March 16 , 1940 , the American College of Dentists presented a plaque to the Army Medical Service Graduate School ( now Walter Reed Army Institute of Research ) in memory of Army dental officer Major Fernando E . Rodriguez for his pioneer research showing the relationship between the Lactobacillus acidophilus and dental caries . On August 31 , 1944 , the War Department of the United States issued General Order No . 71 which renamed the Army General Hospital of Fort Brooke located in the former Ballajá Barracks ( in the grounds of the Fort San Felipe del Morro ) in Old San Juan , the Rodriguez ( 161st ) General Hospital , in honor of Major Rodriguez Vargas . On February 14 , 1949 the Rodriguez General Hospital was closed as a part of the closing of Fort Brooke . The Outpatient Clinic which was located on Fort Buchanan , Puerto Rico was renamed ; the Rodriguez Army Health Clinic and remains in part to this day . Rodríguez Vargas is the only Puerto Rican honored with a plaque and bust situated in front of the Walter Reed Army Institute of Research in Washington , D . C . In the 1950s , the Puerto Rico College of Dental Surgeons honored Rodriguez Vargas with the establishment of the " Dr . Fernando E . Rodriguez Scientific Contest " .