1900J MICROSCOPICAL JOURNAL. 347 



ly increase the transparaucy of organic substances ; and 

 though this is often advantageous, it may also sometimes 

 result in so great a diminution of their reflecting capacity 

 as to make them indifferent mounts. We have given such 

 instructions in elementary mounting as will, we think, 

 enable a beginner to make rapid progress in the art if he 

 is gifted with only a small amount of perseverance and 

 patience, but it must not be forgotten that the actual 

 mounting is but a part of the work required. Numerous 

 subjects will need very careful preparation beforehand, 

 and on the methods adopted and the skill and judgment 

 with which they are carried out will depend much of the 

 result. Many objects will need dissecting. Most dissec- 

 tions, and especially delicate dissections, are done under 

 water, with perhaps a little methylated spirit added if the 

 objecthas previously been soaking forsome time in methy- 

 lated spirit or alcohol. In some cases it will be necessary 

 to fasten the object down, and this may be done with pins 

 on a weighted piece of cork placed inside the dissecting 

 dish, or by running paraffin or some such compound into 

 the bottom as already explained. Watch-glasses with flat 

 bottoms make useful dissecting dishes. Two or three 

 needles set in light wooden handles will be required, with 

 both straight and bent points, and these can readily be 

 manufactured at home, or purchased for a few cente. In 

 buying dissecting knives, we strongly recommend that 

 those with ivory handles be chosen ; they only cost one 

 shilling and nine-pence each, as against eighteen-pence 

 for the ebony-handled ones, while the latter are so brittle 

 as to break with very little pressure. There are a good 

 many shapes of blades sold, but perhaps the most gener- 

 ally useful are the usual scalpel forms, the spear, and the 

 spatulate-shaped ones. Forceps may be either steel, brass, 

 or nickel, but we prefer the steel, which should, of course, 

 be carefully kept clear of rust. A few camel-hair brushes 

 are also necessary, and a pair of fine scissors. Insects gen- 



