The Microscope. ]3 



MOUNTING WHOLE INSECTS. 



A. X. MOORE, M. D., MICKOSCOPIST, CLEVELAND, O. 



IN looking over the average cabinet of mounted insects, it will be 

 found that nearly all are mounted in the old-fashioned yfaj — 

 Boaked in potash and flattened. Whatever beauty such a preparation 

 may have, it must be admitted that it can not instruct the observer 

 to the extent that one mounted in the more modern way would, and, 

 as the majority of American microscopists pay so little attention to 

 this, it may be admissible to say a few words upon the subject. 



Nearly all insects mounted without pressure should be mounted 

 in cells, and the choice of cell material frequently becomes a matter 

 of considerable importance. Glass is probably the best material as 

 a rule; brass cells should not be used with balsam mounts, unless 

 protected by some cement or plated with some other metal, for the 

 balsam will usually turn green. Probably the best cement for 

 attaching the cells to the slides is the best marine glue. Small 

 pieces should be cut up and placed upon the slide. The slide should 

 be gradually and evenly heated, and the cell — also hot — should be 

 carefully lowered into the glue. To insure proper contact with the 

 glue, gently rotate the cell and press it down carefully. Both the 

 slide and cell should be chemically clean before the glue is used at 

 all. After the glue has become hard — which will be when the slide 

 is cold — cut away all superfluous glue with a sharp knife blade, and 

 clean up with chloroform on a piece of fine cloth. 



When the cell is complete, it should be rather thickly coated, 

 inside and out, with a solution of gum containing sufficient glycerine 

 to prevent brittleness. When dry, the insect should be placed in the 

 cell, and none but fresh insects should be used. It is a good plan to 

 keep the insect alive for a few days before the process of mounting 

 is begun, as it will probably clean the dust off of itself better than 

 the microscopist could. It should then be " gradually killed " by 

 chloroform. I say gradually because I mean that it should be 

 quietly put to sleep and not allowed to awaken. This will kill it 

 without shriveling up the legs, etc. The insect may then be placed 

 in the cell and arranged in position with a needle. When satisfac- 

 torily arranged it should be made to adhere to the gum by gently 

 breathing into the cell to soften the gum. When dry — which will 

 depend upon various conditions, such as temperature and conditions 

 of the suiTounding air — place a few drops of strong alcohol in the 

 cell and cover with a large cover glass. After remaining several 



