350 APPENDIX TO CHAPTERS 17. TO IX. 



The rapid fixation of the tissues of the imago, so essential to 

 good results, can only be insured by first washing the whole 

 insect in alcohol to remove the waxy secretion from the integu- 

 ment, unless absolute alcohol is used as a fixative. An exhaust- 

 ing syringe is useful to assist the permeation of the insect by 

 the fixative fluid, but, if alcohol be used for washing, is not 

 essential ; indeed, of late years I have not used it. 



Benzoline has recently been recommended as a substitute for 

 chloroform before imbedding in paraffin. I cannot, however, 

 recommend it, as I am sure it is more destructive to the tissues 

 than chloroform. It has also been recommended instead of 

 turpentine for removing the paraffin from sections. It certainly 

 does so more rapidly, but I consider its use dangerous, and, 

 although cheaper than turpentine, I do not think it should be 

 employed. Xylol is equally dangerous, as its vapour is most 

 inflammable. When used, it ought to be kept in a small bottle, 

 and employed with great caution. A serious accident may 

 readily occur from any carelessness. 



