68 DE-ALCOHOLISATION AND CLEARING AGENTS. 



124. Oil of Bergamot (SCHIEFFERDECKER, Arch. Anat. Phys., 1882 

 [Anat. Abth.], p. 206). Clears 95 per cent, alcohol preparations and 

 celloidin preparations quickly, and does not extract anilin colours. 



Bergamot oil is, I believe, the least refractive of these essences, 

 having a lower index than even oil of turpentine. 



SUCHANNEK (Zeit. wiss. Mik., vii, 1890, p. 158) says that bleached, 

 colourless bergamot oil will not take up much water, whereas a 

 green oil will take up as much as 10 per cent. 



VAN DER STRICHT (Arch, de Bid., xii, 1892, p. 741) says that 

 bergamot oil will, with time, dissolve out the fatty granules of 

 certain ova. 



125. Oil of Origanum (NEELSEN and SCHIEFFERDECKER, Arch. 

 Anat. Phys., 1882, p. 204). Ninety-five per cent, alcohol prepara- 

 tions are cleared quickly, and so are celloidin sections, without 

 solution of the celloidin. Anilin colours are somewhat extracted. 



For work with celloidin sections care should be taken to obtain 

 01. Origani C ret id (" Spanisches Hopfenol "), not 01. Orig. Gallic i 

 ,(v. GIESON ; see Zeit. wiss. Mik., iv, 1887, p. 482). Specimens of 

 origanum oil vary greatly in their action on celloidin sections. 



SQUIRE, in his Methods and Formulae, etc., p. 81, says that origa- 

 num oil (meaning the commercial product) is nothing but oil of 

 white thyme more or less adulterated (see next ), and that the 

 product sold as 01. Origani Cretici is probably oil of marjoram. 



126. Oil of Thyme. FISH (Proc. Amer. Mic. Soc., 1893 ; Zeit. 

 wiss. Mik., xi, p. 503), following BUMPUS, says that for most of the 

 purposes for which origanum oil has been recommended, oil of 

 thyme will do just as well if not better. The red oil is just as efficient 

 as the white for clearing. 



Schimmel & Co., in their Report of October, 1895, p. 69, state 

 that in France white oil of thyme is adulterated with oil of turpentine 

 to the extent of as much as 50 per cent. 



127. Oil of Gaultheria. Used by UNNA (Monatschr. pralct. Derm., 

 Ergtinzungsh, 1885, p. 53) for thinning balsam. The artificial oil, 

 methyl salicylate, is recommended by GUEGUEN (Comp. Bend. Soc. 

 Biol., v, 1898, p. 285) both as a de-alcoholisation and clearing agent and 

 as a solvent of paraffin. The refractive index is 1-53. It is, unfor- 

 tunately, very sensitive to water. 



128. Sandal-wood Oil (NEELSEN and SCHIEFFERDECKER. loc. cit.).- 

 Very useful, but its high price is prohibitive. 



129. Oil of Cajeput. Now much used. I have used it myself and 

 found it to clear well, but to be rather thin. CAENOY and LEBRUN 



