230 CLEARING AGKNTS. 



many purposes, for clearing celloidin sections (for which it 

 is a very good medium) amongst others. 



353. Anilin Oil. This is a very important reagent on 

 account of its ability to clear excessively watery objects. 

 Common anilin oil will readily clear sections from 70 per cent, 

 alcohol, and with certain precautions objects may be cleared 

 from watery media without the intervention of alcohol at all. 

 This property renders anilin valuable in certain cases as a 

 penetrating 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. This may easily be prepared 

 by distilling the common oil (SOCHANNEK, Zeit.f. wiss. Mik., 

 vii, 2, 1890, p. 156). It should be distilled over into a per- 

 fectly dry bottle containing a few pieces of caustic potash 

 (this, being quite insoluble in anilin, may remain in the anilin 

 without being in any way a hindrance to its employment). 

 The first 10 to 12 c.c. of liquid that come over will contain 

 some water, and should be thrown away. The remainder of the 

 distillate should be preserved over the potash, the bottle being 

 closed with a rubber stopper and kept protected from light 

 as far as possible. It is used for preparing for paraffin in the 

 usual way, alcohol objects clearing quickly in it, whilst quite 

 watery objects will make the oil cloudy and require it to be 

 changed once or twice. SUCHANNEK recommends that the 

 objects be not brought direct from the anilin into paraffin, 

 but first soaked for some hours in toluol or xylol the anilin 

 in this process taking the place of the usual alcohol rather 

 than that of the usual clearing agent. 



As above pointed out ( 305), anilin is used for clearing 

 celloidin sections, and is sometimes found very valuable for 

 this purpose. 



354. Xylol, Benzol, Toluol, Naphtha, Chloroform. Too volatile 

 to be recommendable as general clearing agents, but may be 

 used for celloidin sections or for paraffin sections. For these 

 I greatly recommend naphtha. 



355. Absolute Alcohol (SEILEE, Journ. Roy. Mic. Soc., 1882, p. 126). 

 Absolute alcohol is recommended by Seiler for preparing objects for mount- 



