i 
Microscopy. 915 
traversing the sides of the dish is reflected upward, and renders 
the outlines of the object sufficiently distinct for most purposes 
of orientation. 
3. Dissecting Pans.—The most satisfactory material for the 
“filling” to dissecting pans is undoubtedly bees-wax, and for 
ordinary purposes it should be made black by having thoroughly 
Stirred into it while melted a quantity of lamp-black. This mass, 
“tun” into suitably-shaped tin pans—provided with narrow ledges 
f — soldered to the inside just below the prospective surface of the 
wax, to prevent its floating in the dissecting fluid—is serviceable 
for a time, but is destined sooner or later to become worthless, 
owing to the inevitable rusting of the pan. Fortunately there 
have come into the market, within a year or two, heavy glass 
dishes (they are of various proportions) with short legs at the 
four corners, which are suitable in shape for dissecting pans. 
€y Present the advantages of admitting more light upon the 
object and of not rusting. The wax may be prevented from 
floating in the dissecting fluid by pouring into the melted wax in 
€ dish a sufficient quantity of shot to give the desired specific 
gravity to the whole mass. Since these dishes are apparently 
$ «cast in molds and are presumably not of the best quality of 
glass, some care should be used to prevent breakage. This can 
* be readily accomplished by floating the glass dish in a pan of 
water, and gradually raising the temperature of the water to near 
the boiling point. “The hot wax then poured into the glass will 
hot be likely to break it. A convenient size, 25°™ by 15°%™ and 
about gem deep, retails for about forty cents, and can probably 
eae had from most of the glass dealers. Mr. M. G. Cochrane, of 
= Sai Adams & Clark, 65 Franklin street, Boston, can supply 
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When the surface of the wax has become impaired, it may be re- 
“ored either by remeltiag the whole or, more quickly, by direct- 
e from a gas burner downward upon the surface, 
“Dy enough can be melted to accomplish the object. 
Ssecting-trays of various shapes to suit special objects may 
= COR Any irregularities may be repaired by cabo 
of the gas jet.—F, L. Mark, Mus. Comp. Zoöl., Cambridge. 
