118 SERIAL SECTION MOUNTING. 



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. The watery fluid 

 causes the double sheet of collodion to become detached from the 

 glass, holding the sections fast between its folds. It is then easy to 

 stain, wash, dehydrate, and mount in the usual way, merely taking 

 care not to use alcohol of more than 90 to 96 per cent, for dehydra- 

 tion. Weigert recommends for clearing the mixture of xylol and 

 carbolic acid ( 167). 



The series should be cut into the desired lengths for mounting 

 whilst in the alcohol. 



A good method for large and thick sections. 



For BLOCHMAN'S modification see 191. 



STRASSER takes gummed paper instead of the glass plates used in this 

 process. See the papers quoted 192. 



