KREASOTE. 229 



349. Sandal-wood Oil (NEELSEN and SCHIEFFERDECKER, ibid.). 

 "Finest East Indian sandal-wood oil/' price per kilo 50 

 marks (=2 10s.). Somewhat thicker than the last two, 

 light yellow, odour faint, agreeable, evaporation hardly per- 

 ceptible, unchangeable by light, miscible with chloroform 

 balsam and with castor oil. Ninety-five per cent, alcohol^ 

 preparations cleared quickly, celloidin more slowly, anilin 

 colours unaffected. 



Very useful ; its worst fault is its high price. 



350. Turpentine. Generally used for treating sections that 

 have been cut in paraffin, as it has the property of dissolving 

 out the paraffin and clearing the sections at the same time ; 

 but many other reagents (naphtha, for instance) are prefer- 

 able for this purpose (see ante, 283). If used for alcohol 

 objects it causes considerable shrinkage, and alters the struc- 

 ture of cells more than any other clearing agent known to 

 me, unless used in the thickened state, a method which is 

 much liked for some purposes in Germany. Thickened tur- 

 pentine ("Verhartzes Terpentinol" of German writers) is 

 prepared by exposing rectified turpentine in thin layers for 

 some days to the air. All that is necessary is to pour some 

 turpentine 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. Turpentine has, I believe, the lowest 

 index of refraction of all the usual clearing agents except 

 bergamot oil ; it clears objects less than balsam. 



351. Carbolic Acid. Best used in concentrated solution in 

 alcohol. Clears instantaneously, even very watery prepara- 

 tions. This is a very good medium, but it is better avoided 

 for preparations of soft parts which it is intended to mount 

 in balsam, as they generally shrink by exosmosis when placed 

 in the latter medium. It is, however, a good medium for 

 celloidin sections (see above, 305). 



352. GAGE'S Mixture (Proc. Amer. Soc. Micr., 1890, p. 120; 

 Journ. Roy. Micr. Soc., 1891, p. 418). Carbolic acid crystals 

 melted, 40 c.c. ; oil of turpentine, 60 c.c. 



352 a. Kreasote. Much the same properties as carbolic acid. 

 Beech-wood kreasote is the sort that should be preferred for 



