 Quellung reaction

The quellung reaction, also called the Neufeld reaction, is a biochemical reaction in which antibodies bind to the bacterial capsule of "Streptococcus pneumoniae", "Klebsiella pneumoniae", "Neisseria meningitidis", "Bacillus anthracis", "Haemophilus influenzae", "Escherichia coli", and "Salmonella".The antibody reaction allows these species to be visualized under a microscope.