SERIAL SECTION MOUNTING. 127 



If it be desired to stain in a watery fluid, care must have 

 been taken when arranging the sections to let the colloidin 

 of each section overlap that of its neighbours at the edges, 

 so that the ether vapour may fuse them all into one con- 

 tinuous plate. This will become detached from the slide in 

 watery fluids, and may then be treated as a single section. 

 Terpinol may be taken instead of bergamot oil. 



197. APATHY'S Series-on-the-Knife Method (Zeit. wiss. Mik., 

 vi, 1888, p. 168). The knife is well smeared with yellow 

 vaseline, rubbed evenly on, and is wetted with alcohol of 

 70 to 90 per cent. As fast as the sections are cut they are 

 drawn with a needle or small brush to a dry part of the 

 blade, and there arranged in rows, the celloidin of each 

 section overlapping or at least touching that of its neighbours. 

 When a series (or several series, if you like) has been thus 

 completed, the sections are dried by laying blotting-paper 

 on them, and the series is painted over with some of the 

 thinnest celloidin solution used for imbedding, is allowed to 

 evaporate for five minutes in the air, and the knife is then 

 removed and brought for half an hour into 70 per cent, 

 alcohol. This hardens the celloidin around the sections into 

 a continuous lamella, which can be easily detached by means 

 of a scalpel, and stained, or further treated as desired. 



198. WEIGERT'S Collodion Method (Zeit. wiss. Mikr., 1885, 

 p. 490). Slides, or larger plates of glass, are prepared by 

 coating them with collodion in a thin layer, as photographers 

 do, and allowing them to dry (they may be kept thus in 

 stock). Sections (cut wet with alcohol) are got on to one of 

 these (by a roundabout process, not essential), and arranged 

 in order, and gently pressed down with paper. 



Now remove with blotting-paper any excess of alcohol 

 that may remain on or around the sections, pour collodion 

 over them, and get it to spread in an even layer. As soon 

 as this layer is dry at the surface you may write any necessary 

 indications on it with a small brush charged with methylen 

 blue (the colour will remain fast throughout all subsequent 

 manipulations) . 



The plate may now be either put away till wanted in 80 

 per cent, alcohol, or may be brought into a staining fluid. 



