CHAPTER VI. 69 



(La Cellule, xiii, 1897, p. 71) have found it useful for clearing celloidin 

 sections. It dissolves celloidin very slowly and clears without 

 shrinkage. 



130. Oil of Turpentine. Generally used for dissolving out the paraffin 

 from sections; but many other reagents, such as xylol and benzol, 

 are preferable for this purpose. If used for alcohol objects, it causes 

 considerable shrinkage, and alters the structure of cells more than any 

 other clearing agent known to me. Turpentine has, I believe, the 

 lowest index of refraction of all the usual clearing agents except bergamot 

 oil ; it clears objects less than balsam. 



131. Terpinol (liquid, from Schimmel & Co.) is recommended by 

 MAYER, Zeit. wiss. Mikr., xxvi, 1910, p. 523. Clears from alcohol 

 of 90 per cent., or even 80 per cent. One part xylol and^4 

 terpinol has been much used lately. 



132. Carbolic Acid. Best used in concentrated solution in alcohol. 

 Clears instantaneously, even very watery preparations. 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. 



GAGE'S Mixture (Proc. Amer. Soc. Micr., 1890, p. 120). Carbolic 

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



133. Creosote. Much the same properties as carbolic acid. 

 Beech-wood creosote is the sort that should be preferred for many 

 purposes, amongst others, for clearing celloidin sections, for which 

 it is a very good medium. 



134. Anilin Oil. Common anilin oil will readily dear sections from 

 70 per cent, alcohol, and with certain precautions (for which see the 

 paper of SUCHANNEK quoted below) objects may be cleared from 

 watery media without the intervention of alcohol at all. This 

 renders it valuable in certain cases as a medium for preparing for 

 paraffin imbedding. For ordinary work the usual commercial 

 anilin will suffice ; and it is immaterial whether it be colourless or 

 have become brown through oxidation. For difficult work it is well 

 to use a perfectly anhydrous oil. For directions for preparing this 

 see SUCHANNEK, Zeit. wiss. Mik., vii, 1890, p. 156, or the third 

 edition of this work. 



Anilin is chiefly used for clearing celloidin sections. It ought 

 however to be soaked out before mounting by something else 

 (chloroform or xylol for instance for some hours), as if not removed 

 it will brown both the tissues and the mounting medium. 



