MOUNTING INSECTS IN FLUID 5 



sequently may be cut to any size required. In 

 the Halford cabinets, blocks 2j inches square 

 are used. 



The cement for securing the cover is Hollis' Cement. 

 Liquid Glue, which may be obtained from Mr. 

 Charles Baker, optician, of High Holborn. 



The method of manipulation is as follows. 

 Clean the glass with methylated spirit, rubbing 

 it with a silk handkerchief, and fill the cavity 

 ground into the block half- full of 2 per cent, 

 formalin solution. Place the insect in position, 

 and examine it carefully with a lens to make 

 sure that there is no extraneous matter adhering. 

 The cement should then be painted fairly 

 thickly and evenly round the flat top of the 

 cell, care being taken that it does not approach 

 the extreme edge of the cavity. Then fill up 

 the cavity until the fluid presents a convex 

 surface. The precaution should here be ob- 

 served of again examining the contents of the 

 cavity with the lens in case any dust or hairs 

 may have dropped in. 



Take the cover, which must be quite clean, 

 and breathe heavily upon the under-side. Lay 

 the edge along the cemented edge of the cell, 

 and lower gradually into place, the surplus 

 fluid being partly driven out at the opposite 

 side. There will remain a film of fluid which 

 prevents absolute contact between the cover 

 and the cemented surface. This may be 

 drawn off by the use of strips of blotting-paper. 

 It is of importance to avoid all pressure, and, 

 when the surplus fluid has been removed, the 



