70 DE-ALCOHOLISATION AND CLEARING AGENTS. 



135. Xylol, Benzol, Toluol, Chloroform. Too volatile to be 

 recommendable as clearing agents in which it is desired to examine 

 specimens, but very useful for preparing paraffin sections for balsam. 

 Of the three first-mentioned liquids, benzol is the most volatile, then 

 toluol, and xylol is the least volatile, in the proportion of 4 : 5 : 9 

 (SQUIRE, Methods and Formulce, p. 20). Chloroform is injurious to 

 some delicate stains, but is in other respects an excellent de-alcoholisa- 

 tion agent, as it will take up a good deal of water, if any be left in 

 the preparations. I consider it too volatile to be safe to use before 

 balsam. Xylol is the best of these in that respect. 



Both xylol and toluol are liable to become acid if kept in only 

 partially filled vessels. 



