When a blood film containing anthrax bacilli is stained using polychrome methylene blue for a few seconds and observed under microscope, a purplish coat of amorphous material is seen around a blue stained bacilli. The amorphous purple material is the capsule. This is called Mc Fadyean’s reaction and is used in the presumptive diagnosis of anthrax in animals.

1. Wool sorters disease
2. Microbiology – MCQ 11 – A person working in an abattoir presented with a papule on hand, which turned into an ulcer.
3. Safety pin appearance is seen in
4. Medicine – MCQ 112 – Infective dose of Salmonella typhi