Set of six slides includes: Staphylococcus aureus , pus organism, smear from culture Bacteria from mouth, ideal for demonstrating Gram positive and negative bacteria Streptococcus lactis , milk souring organism, smear from culture showing short chains Escherichia coli , colon bacteria, smear Spirillum volutans , a very large spirillum, smear Bacillus subtilis , hay bacillus, smear showing bacilli and spores doubly stained