<Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (June 2008) </Td> </Tr> <P> There are generally three types of fixation processes depending on the initial specimen: </P> <P> Heat fixation: After a smear has dried at room temperature, the slide is gripped 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 . Routinely used with bacteria and archaea . Heat fixation generally preserves overall morphology but not internal structures . Heat denatures the proteolytic enzyme and prevents autolysis . 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 . </P> <P> Immersion: The sample of tissue is immersed in fixative solution of volume at a minimum of 20 times greater than the volume of the tissue to be fixed . The fixative must diffuse through the tissue to fix, so tissue size and density, as well as type of fixative must be considered . This is a common technique for cellular applications . Using a larger sample means it takes longer for the fixative to reach the deeper tissue . </P>

What other methods of fixation can be used for smear preparation