The Nissan Path

Iodine is one component in the Staining Solutions known as Gram staining, used in microbiology. Lugol's solution or Lugol's iodine (IKI) is a brown solution that turns black in the presence of starches and can be used as a cell stain, making the cell nuclei more visible.
https://www.lobachemie.com/staining-sol ... no-na.aspx