39 FLUID MOUNTS. 



medium. To place the cover glass in position, rest one side of it on 

 the edge of the ring and lower it slowly over the object, allowing 

 the surplus mounting fluid to be forced out on one side. Press the 

 cover firmly in position. Before sealing fluid mounts, fasten the 

 cover in place by applying three or four small drops of sealing mix- 

 ture at the edge of the cover glass at different points. As soon as 

 dry, these hold the cover in place and allow the mount to be per- 

 manently sealed. Cells may be made of glass, zinc, bone, or cellu- 

 loid rings which can be secured of any regular dealer in micro- 

 scopical supplies ; or rings can be cut from sheet lead, tin, paper, or 

 wax, and fastened in position with shellac or marine glue applied to 

 the base of the cell and then held firm, by the ring, against the 

 slide until dry. Seal around the outside and when ready for use, 

 apply a light coat of sealing mixture to the top, to hold the cover- 

 glass in place. When the object is mounted, seal the whole prepa- 

 ration as in the case of ordinary mounts. 



Objects can be easily mounted dry in cells, in which case they 

 should be held in position by fastening them to the slide with a 

 little glycerin jelly, collodion, or gelatine. Fluid mounts should be 

 examined from time to time to repair any that may not have been 

 perfectly constructed. 



