EXAMINATION AND PRESERVATION MEDIA 227 



487. Venice Turpentine (Vossklkr, Zeit. iviss. Mile, 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 ha?malum stains fade in it. 



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

 Venice turpentine and neutral absolute alcohol. 



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

 medium by some workers. To prepare it, 2)our some oil into a 

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

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



489. Gilson's Sandarac Media (La Cellule, xxiii, 1906, p. 427 : 

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

 difficulty of preparation. 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 = 1-485. 



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

 paraldehyde, n = 1-483. There are two sorts of this, the colour- 

 less 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, " 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. 

 We generally prefer alcohol of 95 per cent, (absolute is dangerously 

 volatile for sections). In difficult cases you may pass through a 

 mixture of the medium and the solvent. Dr. Alexander some- 

 times used paraldehyde containing some terpineol. 



These media icork very kindly, and do not dry too rapidly. Dr. G. A. 

 Alexander, like one of us, has experienced bad fading of ha^matoxylin 

 preparations mounted in euparal. Gatenby noted years ago that 

 euparal turned Ehrlich's ha?matoxylin slides a nasty colour, followed 

 soon by fading. We cannot explain this phenomenon, but, as Dr. 

 Alexander points out to us (in Uteris), it does not occur with eosin- 

 methylen blue preparations, and most of the coal-tar dyes seem to last 

 well in euparal. 



Dr. Rees Wright (Aim. Trap. Med. c<b Pnrasit., vol. xxii, 1927) also 

 states that he has found euparal invaluable for mounting blood films 

 of the Romanowsky type, which have not faded for over six years. 

 This author also uses euparal as a mountant for nematodes and insect 

 genitalia, the objects being transferred from 70 per cent, alcohol to 

 phenol, and when cleared to euparal. 



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