46 ROYAL ASIATIC SOCIETY, (CEYLON BRANCH.) 



ON THE PREPARATION AND MOUNTING OF 

 INSECTS FOR THE BINOCULAR MICROSCOPE. 

 BY S. GREEN, Esq. 



(Read at General Meeting November 2, 18 74. J 

 When objects possessing a certain amount of thickness 

 are examined under the binocular microscope, it is observed 

 that they stand out in much bolder relief than when viewed 

 under the minocular microscope. This stereoscopic effect 

 is produced by a prism placed immediately over the object- 

 glass " by which the two eyes applied to the two eye-pieces 

 respectively, receive through the two halves of the objective 

 two magnified images of the object under examination, differ- 

 ing from each other in perspective projection, as if the object 

 actually enlarged to the dimensions of its image had been 

 viewed by both eyes at once at a moderate distance."* 



The received method of mounting insects for microscopical 

 examination, and that was in vogue long before the intro- 

 duction of the binocular, is first to immerse them in Liquor 

 Potassa, in which they should remain for two or three days 

 according to the amount of muscle and intestine that has to 

 be dissolved within the skin of the insect, the cuticle itself 

 being insoluble in potash. The insect is then removed from 

 the Potassa and carefully washed in distilled water with a 

 camel's hair pencil, to remove any dirt that may adhere to it. 

 This being done, it is floated on to a slip of glass three inches 

 by one (the standard size for glass slips for mounting objects 

 for the microscope), and wings, legs, &c, arranged with the 

 brush, according to the skill of the operator. Another slip 

 of glass of the same dimensions is then laid over the insect, 



* Carpenter's Microscope and its Revelations. 



