192 Modern Microscopy 



shellac cement, as directed for balsam mounts. Apply a 

 coat of cement to the upper side of the cell, and allow it to 

 nearly dry. Fill the cell with glycerine, and put the insect 

 into it ; spread out the wings, legs, etc. Clean and warm 

 a cover-glass, and apply its edge to the cell ; press down, 

 and be sure that it adheres to the cement all round. Wash 

 away the excess of glycerine with some water, and dry the 

 slide with a soft cloth. When quite dry, apply a ring of 

 cement, and when this has dried, add another coat of black 

 shellac cement. 



The processes described only refer to the study of the 

 external parts of insects ; all the soft tissues and internal 

 organs will, of course, have been destroyed by the potash. 

 Soft internal organs must be dissected out of the specimen 

 while under water. 



Procure a guttapercha dissecting-dish, lay the insect in 

 it, and secure with pins in the desired position. If the 

 abdominal or thoracic viscera are required, lay the insect 

 on its back; if the nervous system, on its ventral surface, 

 Fill the dish with water, and with a pair of sharp-pointed 

 scissors cut through the chitinous skin on each side of the 

 abdomen, taking care not to cut too deeply so as to injure 

 the internal organs ; then with a pair of forceps raise and 

 remove the skin. The organs may now be removed with 

 the aid of a pocket-lens, and washed in distilled water ; 

 then stain in borax carmine for several minutes, wash in 

 methylated spirit ; then immerse in acidulated alcohol for 

 a few minutes, dehydrate, clear in clove-oil, and mount in 

 Canada balsam. 



If desirable to mount the specimen in glycerine, stain as 

 above, then wash away all trace of spirit with water, and 

 mount in glycerine jelly ; if the specimen requires a cell, 

 it must be mounted in glycerine. 



Salivary glands of cockroaches and crickets, gizzards of 

 beetles, and stings of bees and wasps, may be easily re- 

 moved in the following way : Place the specimen whole 

 and while quite fresh in water, cover with a piece of paper 



