48 On Mounting. 



painting round the cover glass with either Dammar 

 varnish or Hollis' glue, taking care that only the ex- 

 treme edge of the cover glass is included. It will be 

 necessary to give a second and third coat if Dammar 

 varnish is used, at intervals of a few days. 



It will be found a good plan to seal first with Dam- 

 mar varnish, and afterwards to cover this with Hollis' 

 glue, as it makes the preparation more secure, and it is 

 absolutely necessary to have them sealed with Hollis' 

 glue when oil immersion lenses are to be used, as the 

 cedar oil does not touch it, while it dissolves Dammar 

 varnish at once. 



Specimens carefully prepared in the above manner 

 may be kept for years without deteriorating. 



MOUNTING IN CANADA BALSAM OR DAMMAR. 

 Canada balsam mounting fluid is prepared by mixing : 

 Canada balsam, 105 parts. 

 Turpentine, 35 parts. 

 Chloroform, 35 parts. 



Dammar varnish is prepared thus : 

 Take of 



Gum Dammar in powder, i oz., and dissolve it in 



turpentine, 1-J- oz. Filter. 

 Gum mastic, i oz., and dissolve it in chloroform, 



2 oz. Filter. 

 Mix the two solutions and filter again. 



Put in stoppered bottles, and see that they are per- 

 fectly free from moisture before using. A small drop- 

 bottle of each of these fluids must be kept for daily 



