40 



THE BRITISH NATURALIST. [February 



MICROSCOPY. 



Mounting Entomological Objects for the Microscope. — After 

 soaking the insect in liquor potassa until it is transparent, boil it in the 

 same, — cold liquor potassce will not dissolve oil, — then boil it in two lots 

 clean distilled water, so that the alkali may be completely washed away. 

 If necessary stain it with, say, aniline blue fluid. This is the only stain 

 which will stain chitin well. Staining generally is a great improvement, 

 for besides adding to the beauty of the insect, it brings up details other- 

 wise unnoticed. Wash off the superfluous fluid in alcohol ; from there 

 transfer it to oil of cloves, in which it may be kept until it is wanted. To 

 mount the object lay it on a slide arranging it neatly, and suck up with 

 a pipette as much of the oil of cloves as possible, and place three small 

 beads, or pieces of cover glass, around to support the glass cover. 

 These must be slightly thinner than the object ; put on the thin glass 

 cover, securing it with a spring clip, now let the liquid balsam run under 

 by capillary attraction. It is necessary that the cover should just touch 

 the object which would otherwise be washed away by the wave ot 

 balsam. Balsam and benzoline is the most suitable medium. 



Muscles of Insects. — To retain the muscles of insects for microscope 

 slides, soak the insects in ether, which dissolves fat, but has no other 

 effect ; mount as usual. 



ARACHNIDA. 



New Method of Mounting Spiders. — This method is very simple, 

 and has the advantage over other methods in the spider being fully 

 displayed, and able to be withdrawn from the jar if required for 

 examination under the stage of the microscope. Take the spider from 

 the killing bottle, and for a minute or so allow it to remain on a piece of 

 clean blotting paper to absorb the superfluous moisture, then take 

 an opal slip, smear the surface with a slight coating of gum tragaca?ith 

 over the spot to be occupied by the specimen, place it, and arrange the 

 legs in their natural position. After standing for about twenty minutes 

 to dry the tragaca?ith, the slip can be placed into a jar of spirit, and the 

 mounting is complete. Space may be left on the slip for additional - 

 specimens, which can be arranged in a similar manner if care be taken 

 to dry the surface ot the opal slip thoroughly before applying the gum. 

 The gum, being colourless, is practically invisible, — a great advantage in 

 the appearance of the mount, — while to remove a specimen it is only 

 necessary to moisten the slip with warm water, and the specimen, 

 becomes detached. It is advantageous to mount a few specimens show-; 



