CH. J VI. ] COL L OD ION SECTIONING. 1 6 1 



ether-alcohol (equal parts of sulphuric ether and 95$ alcohol) on the 

 sections to moisten them. This will melt the collodion and fasten the 

 sections to the slide. Allow the slide to remain in the air till the sur- 

 face begins to look slightly dull or glazed. 



Sometimes, especially when the air is moist, the sections wrinkle 

 badly when the ether-alcohol is put on to fasten them to the slide. 

 The excessive wrinkling can be avoided by using one part alcohol and 

 two parts ether instead of using equal parts of each. Perhaps also it 

 would be advantageous in this case to use absolute alcohol. 



Fig. 133. Pipette for adding liquids drop- 

 wise and for -washing preparations. {Whit- 

 all, Tatum & Co.) 



S 262. Removing the Oil from the Sections. — As soon as the 

 ether-alcohol has evaporated sufficiently to leave the surface dull, place 

 the slide in a jar of ordinary commercial beuzin. It may be left here a 

 day or more without injury to the sections, but if moved around in the 

 jar the oil will be removed in three to five minutes. From the benzin 

 transfer to a jar of 95% alcohol to wash away the benzin. One may 

 use alcohol in the beginning, but it dissolves the oil far less rapidly than 

 the benzin. The slide may remain in the alcohol half a day or more if 

 one wishes, but a stay of five minutes or a thorough rinsing of half a 

 minute or so by moving the slide around in the alcohol will suffice. 



£ 263. Staining the Sections with an Alcoholic Stain. — If an 

 alcoholic stain containing 50^ or more alcohol (for example, hydro- 

 chloric acid carmine in 70% alcohol) is used, the slide may be removed 

 from the 95% alcohol, drained somewhat and then the stain poured 

 upon the sections, or preferably, the slide immersed in a jar of the stain. 

 The stain is finally washed away with 67% or stronger alcohol, the sec- 

 tions dehydrated in 95'/ alcohol, cleared and mounted in balsam. 



§ 264. Staining the Sections with an Aqueous Dye. — In staining 

 with a watery stain, the slide bearing the sections is transferred from 

 the 95 r /c alcohol and plunged into a jar of water, and either allowed to 

 remain a few minutes or moved around in the water a moment. Then 

 it is placed horizontally, and some of the stain placed on the sections 

 with a pipette, or preferably, it is immersed in a jar of the stain ; in 

 case of immersion, however, the slide should stand vertically or nearly 

 so, then any particles of dust, etc., in the stain will settle to the bottom 

 of the vessel and not settle on the sections. When the sections are 

 stained, usually within five minutes, they are thoroughly washed with 

 water either by the use of a pipette or preferably by immersing in a jar 

 1 1 



