Semi-thin sections don't always want to stick to glass slides, but subbing slides is usually not needed. For sections about 2 μm thick and no larger than 4 mm on a slide, this simple method works well for me:

1. 1) Clean 1x3 inch glass slides with an ethanol rinse, then air dry at room temperature or blow down with a hair dryer.

2. 2) Collect sections on a drop or two of distilled water on the slide, transferred there from the microtome with a clean fine tipped artists brush. Collect about 8-12 sections per drop.

3. 3) Warm the slide beneath the water drop from below using an alcohol lamp, fairly hot, but not to boil, of course. After drying by heating the sections stick quite well.

4. 4) Stain, usually with 0.2 μm filtered toluidine blue, again heating but gently this time, for about a minute, until stain “develops” the section.

5. 5) Rinse that stain off with distilled water from a squirt bottle, even directing the spray right onto the sections to get rid of any precipitate. Dry again gently with flame.

The heating is the trick. There should not be any need for subbing or otherwise treating slides other than cleaning them.