CHAPTER XIX. 227 



Dr. S. G. SCOTT of Oxford used both damar and colophonium instead 

 of balsam, and very few of his preparations left after his decease are 

 good. A large number have become granular. 



REHM (Zeit. wiss. Mik., ix, 1893, p. 387) dissolves 1 part colophonium 

 in 10 of benzin. Solutions in chloroform or xylol are also used by some, 

 see NISSL in Encycl. mik. Techn., ii, p. 274. 



447. Venice Turpentine (VOSSELER, Zeit. wiss. Mik., vi, 1889, pp. 292 

 et seq.). Commercial Venice turpentine is mixed in a tall cylinder glass 

 with an equal volume of 96 per cent, alcohol, allowed to stand in a warm 

 place for three or four weeks, and decanted. Preparations may be 

 mounted in this medium direct from absolute alcohol. Celloidin 

 sections can be mounted direct from 96 per cent. Stains keep well, 

 according to VOSSELER, but MAYER finds hsemalum stains fade in it. 



SUCHANNEK (ibid., vii, 1896, p. 463) prepares it with equal parts of 

 Venice turpentine and neutral absolute alcohol. 



448. Thickened Oil of Turpentine has been used as a mounting 

 medium by some workers. To prepare it, pour some oil into a 

 plate, cover it lightly so as to protect it from dust without excluding 

 the air, and leave it until it has attained a syrupy consistency. 



449. GILSON'S Sandarac Media (La t Cellule, xxiii, 1906, p. 427 : 

 the formulae have not been published, on account of the extreme 

 difficulty of preparation, but the products are on sale by Griibler & 

 Hollborn, even if not listed). There are three of these. They are 

 all of them solutions of gum Sandarac in " Camsal " and other 

 solvents (" Camsal " is a liquid formed by the mutual solution of 

 the two solids salol and camphor). 



(1) Camsal balsam (baume au camsal), propylic alcohol formula ; 

 a mixture of sandarac, camsal, and propylic alcohol, n = 0-478. 



(2) Camsal balsam, isobutylic alcohol formula, n = 1485. 



(3) Euparal,* a mixture of camsal, sandarac, eucalyptol, and 

 paraldehyde, n = 1483. There are two sorts of this, the colourless 

 and the green (" euparal vert "), the latter containing a salt of 

 copper, which intensifies hcematoxylin stains. 



Objects may be prepared for mounting in camsal balsam by a 

 bath of propylic or isobutylic alcohol ; and for euparal by a bath of 

 the special solvent (supplied by Griibler & Hollborn under the name 

 of " essence d' euparal "). But this is not necessary. Objects may 

 always be mounted direct from absolute alcohol, and even at a pinch 

 from alcohol of 70 per cent. I myself generally prefer alcohol of 

 95 per cent, (absolute is dangerously volatile for sections). In 



* Now manufactured by Flatters & Garnett (11) according to 

 Gilson's original formula. 



152 



