132 MICROSCOPIC OBJECTS. 



are very rare, and thus we have httle choice in the selection. 

 When this happens, it is always wise to commence our 

 operations on the most defective and conclude with the 

 perfect. By this means we shall acquire facihty and ex- 

 perience, which will be more profitable as we proceed. 



In this little work the principal points to be attended 

 to will be given ; but so numerous and varied are the 

 subjects for the microscope, that it will be impossible 

 to meet every individual case that may occur. An atten- 

 tive perusal of this work and the ' Microscopic Illustra- 

 tions,' with a few days' practice, will enable the student 

 in these matters to overcome most of the difficulties, and 

 to furnish himself with a collection of objects that will 

 afford an endless variety of subjects for investigation and 

 contemplation. 



To Clean the Specimens. — If the object is to be mounted 

 whole, the fii'st process is to thoroughly cleanse it. This 

 is done either by brushing it with a camel's hair pencil or 

 Vv^ashing in water or turpentine. If it be a hard and brittle 

 creature, it must be soaked in hot water; and as fresh in- 

 sects contain much fat, a httle caustic eJkah should be 

 added. "WTien thus softened, the insect, if intended for an 

 opaque object, is to be spread out on a piece of cork and 

 held in a proper position until dry by means of smaU pieces 

 of card pinned down to the cork ; these pins and card are 

 called by entomologists braces. AMien the specimen 

 has hardened, the braces can be removed, and the object 

 is ready to be fastened by gum or cement to a disc, which 

 \^all be described in a subsequent page. 



