116 SERIAL SECTION MOUNTING 



February, 1893). Slides, or glass plates of any size, are coated with 

 a solution made of — 



Syrupy solution of powdered candy-sugar 



made with boiling distilled water . 30 c.c. 



95 per cent, alcohol . . . . 20 ,, 



Transparent syrupy solution of pure 

 dextrin made by boiling with distilled 

 water . . . . . . 10 ,, 



They are dried slowly for two or three days until the surface is 

 just sticky to the moist finger. Paraffin sections are arranged and 

 heated for a few minutes to a temperature slightly above the melting- 

 point of the paraffin. The paraffin is removed by some solvent, and 

 this in turn by absolute alcohol. The alcohol is poured off, and the 

 sections are covered with solution of celloidin. The plates are left 

 to evaporate for ten minutes in a horizontal position, then brought 

 into water, in which the sheet of celloidin with the sections soon becomes 

 detached, and may be further treated as desired, e.g. as in Weigert's 

 process, § 220. The evaporation must not be artificially hastened. 



Dimmer {Zeit. wiss. Mik., xvi, 1899, p. 44) coats the slides 

 with a solution of about 16 parts of gelatin in 300 of warm water, 

 and dries them (two days), and proceeds in other respects as 

 above. 



A good method for large sections, equally applicable to paraffin 

 sections, to celloidin sections, and to sections of material that has 

 not been imbedded at all. 



For Blochman's modification of Weigert's process, by means of 

 which large sections can be preserved unmounted, see Zeit. wiss. Mik., 

 xiv, 1897, p. 189. 



214. Strasser's Collodion Paper Method (ibid., iii, 1886, p. 346). 

 This is an extremely complicated modification of Weigert's method for 

 celloidin sections, and is only adapted for use with Strasser's auto- 

 matic ribbon-microtome. See Zeit. wiss. Mik., iii, 1886, p. 346 ; vi, 

 1889, p. 154 ; vii, 1890, pp. 290 and 304 ; ix, 1892, p. 8 ; xii, 1895, 

 p. 154 ; and xiv, 1897, p. 39 ; also Schoenemann, ibid., xix, 1903, 

 p. 333 ; Strasser, ibid., p. 337 ; and Ruppricht, ibid., xxviii, 1912, 

 p. 281. 



METHODS FOR WATERY SECTIONS 



215. Fol's Gelatin (Fol, Lehrb., p. 132). Four grammes of 

 gelatin are dissolved in 20 c.c. of glacial acetic acid by heating 

 on a water-bath and agitation. To 5 c.c. of the solution add 

 70 c.c. of 70 per cent, alcohol and 1 to 2 c.c. of 5 per cent, aqueous 

 solution of chrome-alum. Pour the mixture 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 water 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. 



