16 T. E. WALLIS ON THE USE OF AMYLIC ALCOHOL 



A good clearing and dehydrating agent for use with amyl- 

 sandarac is made by dissolving one part by weight of phenol 

 crystals in one part by volume of amylic alcohol, a liquid which 

 may be conveniently named amyl-phenol. This substance is 

 superior to clove oil and turpentine because it does not cause 

 the undesirable hardening and shrinking efiects which these oils 

 produce. It is also preferable to liquefied phenol (liquid carbolic 

 acid) because it contains no water and will abstract small amounts 

 of water from objects immersed in it. From this reagent pre- 

 parations may be transferred directly to the mountant. 



To mount a whole spider or insect without pressure in sandarac 

 one proceeds as follows : Steep the specimen in 10 per cent, 

 caustic soda or potash until thoroughly relaxed, transfer to water, 

 glacial acetic acid, amylic alcohol and amyl-phenol in succession, 

 allowing time in each case for a thorough penetration by the 

 liquid used. The object is next placed underside uppermost 

 upon a clean cover-glass, to which three clear-glass beads of a 

 suitable size have been previously fixed by some of the mountant. 

 The legs and other appendages are arranged, if necessary, with 

 a needle or brush, the object is covered with amyl-sandarac and 

 allowed to stand freely exposed to the air, but carefully protected 

 from dust. During these operations the cover-glass is best 

 supported on a cork whose smaller end'is a little less in diameter 

 than the cover- glass. As the solvent evaporates, further quan- 

 tities of the mountant are added until the layer of resin is 

 sufficient to completely embed the object. A drop of amyl- 

 sandarac is now placed in the centre of a microscope slide, and 

 a second drop on the resin covering the object ; the cover- glass 

 with the object is then carefully picked up and inverted upon 

 the slide. As the mountant shrinks under the cover-glass, it 

 is replaced by fresh quantities allowed to flow underneath by 

 capillary attraction. A very satisfactory preparation may be 

 thus obtained. 



It will be noticed that I have recommended supporting the 

 cover- glass during the evaporation of the solvent upon a cork, 

 which should be from 4 to 6 mm. less in diameter than the cover- 

 glass. It is not possible to place the cover- glass on a glass 

 'slide as is generally recommended (4) for benzol- or xylol- 



