<prompt> Mc fayden reaction seen with which organism ?Clostridium perfringensClostridium botulinumBacillus cereusBacillus anthracis  <response>: Ans. is d i.e., Bacillus antracis Mc Fadveans reaction When blood films containing anthrax bacilli are stained with polychrome methylene blue for a few seconds and examined under microscope, an amorphous purplish material is noticed around bacilli. This represents the capsular material and is characteristic of the anthrax bacillus. 