2. Hold the slide in the fingers of one hand and warm cautiously over the flame of a Bunsen burner, touching the under surface of the glass from time to time on the back of the other hand. As soon as the slide feels distinctly warm to the skin, the paraffin section will flatten out and all wrinkles disappear. (The slide with the section floating on it may be rested on the top of the paraffin bath for two or three minutes, instead of warming over the flame as here described.) 3. Cautiously tilt up the slide and blot off the excess of spirit with blotting paper, leaving the section attached to the centre of the slide. 4. Place the slide in a wire rack (Fig. 75), section downward, in the "hot" incubator for twelve to twenty-four hours. At the end of this time the section is firmly adherent to the glass, and is treated during the subsequent steps as a "fixed" cover-glass film preparation. NOTE.--If large, thick sections have to be manipulated, or if time is of importance or acids are used during the staining process, it is often advisable to add a trace of Mayer's albumin to the alcohol before floating out the section. If this substance is employed, a sojourn of twenty minutes to half an hour in the "hot" incubator will be found ample to ensure firm adhesion of the section to the slide. The albuminous fluid is prepared as follows: [Illustration: FIG. 75.--Section rack.] ~Mayer's Albumin.~-- Weigh out Salicylate of soda 1 gramme and dissolve in Glycerine 50 c.c. Add White of egg 50 c.c. Mix thoroughly by means of an egg whisk. Filter into a clean bottle. As an alternative method paint a thin layer of Schallibaum's solution on the slide with a camel's hair pencil; lay the section carefully on this film and heat gently to fix the section. _Schallibaum's solution_: Clove oil 30 c.c. Collodion 10 c.c. Keep in a dark blue bottle in a cool place. ~Staining Paraffin Sections.~-- 1. Warm paraffin section over the Bunsen flame to soften (_but not to melt_) the paraffin, then dissolve out the wax with xylol poured on from a drop bottle. 2. Remove xylol by flushing the section with alcohol. 3. If the tissue was originally "fixed" in a corrosive sublimate solution, the section must now be treated with Lugol's iodine solution for two minutes and subsequently immersed in 90 per cent. alcohol to remove all traces of yellow staining. 4. Wash in water. 5. Stain deeply, if using a single stain, as the subsequent processes decolourise. 6. Wash in water, decolourise if necessary. 7. Flood with several changes of absolute alcohol to dehydrate the section. 8. Clear in xylol. (Oil of cloves is not usually employed, as it decolourises the section.) 9. Mount in xylol balsam. SPECIAL STAINING METHODS FOR SECTIONS. ~Double-staining Carmine and Gram-Weigert.~--