Heat fixation

Heat fixation is the procedure used to adhere a bacterial smear to a glass slide for viewing by a compound microscope.

After a smear has been allowed to dry at room temperature, the slide is gipped by tongs or a clothespin and passed through the flame of a Bunsen burner several times to heat-kill and adhere the organism to the slide. Heat fixation cannot be used in the capsular stain method as heat fixation will shrink or destroy the capsule (glycocalyx) and cannot be seen in stains.