bacillus in patients, hoping to develop antisera and vaccines that would protect against infection. In many patients, but not all, the bacteria were found. Failures to isolate B. influenzae (now known as Haemophilus influenzae) were generally ascribed to inadequate technique, as the bacteria were notoriously difficult to culture. The first blow to Pfeiffer's theory came from Peter Olitsky and Frederick Gates at The Rockefeller Institute. Olitsky and Gates took nasal secretions from patients infected with the 1918 flu and passed them through Berkefeld filters, which exclude bacteria. The infectious agent — which caused lung disease in rabbits — passed through the filter, suggesting that it was not a bacterium. Although the duo had perhaps isolated the influenza virus (which they nevertheless referred to as an atypical bacterium called Bacterium pneumosintes), other researchers could not reproduce their results. In 1896, Pfeiffer isolated micrococcus catarrhalis that is the cause of laryngitis. M catarrhalis also causes bronchitis, and pneumonia in children and adults with underlying chronic lung disease. It is occasionally a cause of meningitis. Richard Pfeiffer also invented a universal staining for histological preparations. After completing his education at the gymnasium in Świdnica, Pfeiffer studied medicine at the Kaiser Wilhelms Akademie in Berlin from 1875 to 1879. After completing his studies he was conferred doctor of medicine in 1880 and subsequently served as an army physician and bacteriologist until 1889. He was a student of Robert Koch (1843–1910), and from 1887 to 1891 worked as Koch's assistant in the Institute of Hygiene in Berlin. In 1891, he was entrusted with the leadership of the scientific department of the Institute of Infectious Diseases in Berlin. In 1897, Pfeiffer joined the German expedition under Robert Koch to India to investigate the plague. The following year he went to Italy with Koch to do research on malaria. He moved to Königsberg to enter the chair of hygiene in 1899, succeeding Erwin von Esmarch (1855–1915). He remained in that city until 1909, when he moved on to the same chair in Breslau. Pfeiffer retired there as emeritus in 1925. References 1858 births 1945 deaths People from Krotoszyn County German bacteriologists 19th-century German physicians Influenza researchers People from the Province of Posen Academic staff of the University of Königsberg Academic staff of the University of Breslau 20th-century German physicians