SERIAL SECTION MOUNTING. 147 



ture on to the slide and allow it to dry. In a few hours the 

 gelatin passes into the insoluble state. It retains, however, 

 the property of swelling and becoming somewhat sticky in 

 presence of water. The slide may then be immersed in 

 \\ator containing the sections ; these can be slid into their 

 places, and the whole lifted out : the sections will be found 

 to be fixed. 



This method is specially intended for sections made under 

 water, large celloidin sections amongst others. 



for Celloidin Sections. 



191. The Albumen Method. I find that celloidin sections 

 may be mounted on Mayer's albumen, and have the celloidin 

 removed, if desired, by putting them into ether-alcohol. Care 

 must be taken to press them down very thoroughly on to the 

 albumen. 



So also JORDAN (Zeit. f. wins. Mik., xv, 1, 1898, p. 54; 

 Joum. Roij. Mic. Soc., 1898, p. 600), who coagulates the 

 albumen by heat, the sections being covered with a layer of 

 tissue-paper and a second slide over it, to prevent them from 

 drying through the heat. 



192. SOMMERS' Ether Method (Amer. Hon. Mic. Journ., 1887, 

 p. 7:5; Zeit. f. wis*. Mile., iv, 4, 1887, p. 482; Journ. Roy. 

 Mi<\ Soc., 1887, p. 523). Place the sections in 95 per cent. 

 alcohol for a minute or two, arrange on the slide, and then 

 pour over the sections sulphuric ether vapour, from a bottle 

 partly full of liquid ether. The celloidin will immediately 

 soften and become perfectly transparent. Place the slide in 

 80 per cent, alcohol, or even directly in 95 per cent, if 

 desired. The sections, it is said, will be found to be firmly 

 fixed, and may be stained if desired. I have not myself 

 found this method safe. 



SCHIEFFERDECKER (Zeit. f. wi**. Mil'., v, 4, 1888, p. 507) 

 recommends that the slide be one that has been previously 

 prepared with a layer of collodion if it is desired to stain on 

 the slide ; but if not a clean slide is perfectly sufficient. The 

 ^lide may, of course, be treated with ether vapour in a prepa- 

 ration glass or similar arrangement. 



GAGE (Proc. Amer. Soc. Mic., 1892, p. 82) advises that the 



