@article{mbs:/content/journal/micro/10.1099/00221287-5-1-54, author = "Burnet, F. M.", title = "A Genetic Approach to Variation in Influenza Viruses: 2. Variation in the Strain NWS on Allantoic Passage", journal= "Microbiology", year = "1951", volume = "5", number = "1", pages = "54-58", doi = "https://doi.org/10.1099/00221287-5-1-54", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-5-1-54", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "When the strain NWS of influenza virus, which is adapted to multiplication in mouse brain, is submitted to allantoic passage in the chick embryo, it maintains its original character if passed at limiting infective dilutions. When passage is made with a low dilution of the same virus preparation the strain changes toward a more normal character. These phenomena are regarded as providing formal proof that the changes are mutational in origin.", }