48 Animal Micrology 



following precautions may prevent the defect: (1) Leave the object 

 in the paraffin bath longer. (2) See that it is entirely free from the de- 

 alcoholizing fluid before placing it into the melted paraffin. Objects 

 which have been immersed in cedar oil are particularly subject to this 

 defect. For this reason xylol is better than cedar oil for dealcoholization 

 in general work. (3) If the object is impervious to paraffin or very friable, 

 as are many ova, some other method must be tried. Consult memoranda 

 8 and 9; see also the celloidin method (chap, vii) or the combination 

 celloidin-paraffm method (chap, vii, memorandum 8). 



9. The Ribbon Twists or Curls about or Clings Closely to the Side of the 

 Knife. This is due to the electrification of sections. If the fault is 

 excessive it is best to postpone the cutting until the atmospheric con- 

 ditions have changed. 



