148 PREPARATION AND MOUNTING 
Sections oF Bont.—With the aid of the microscope few 
fragmentary remains have proved so useful to the geologist 
and students of the fossil kingdom as these. From a single 
specimen many of our naturalists can tell with certainty to 
what class of animal it has once belonged. To arrive at 
this point of knowledge much study is necessary, and sections 
of various kinds should be cut in such a manner as will best 
exhibit the peculiarities of formation. The methods of 
accomplishing this will now be considered. It may, how- 
ever, be first mentioned that the chippings of some bones 
will be found useful now and then, as before stated with 
flint, though this is by no means a satisfactory way of pro- 
ceeding. Sometimes the bones may be procured naturally so 
thin that they may be examined without any cutting; and only 
require mounting dry, or in fluid, as may be found the best. 
When commencing operations we must provide the same 
apparatus as is needed in cutting sections of teeth, before 
described. A fine saw, like those used for cutting brass, 
&c., two or three flat files of different degrees of coarseness ; 
two flat “sharpening” stones; and a leather strop with 
putty-powder for polishing. As thin a section as possible © 
should first be cut from the part required by the aid of the 
fine saw; and it is better when in this state to soak it for 
some short time in camphine, ether, or some other spirit to 
free it from all grease. With the aid of a file we may now 
reduce it almost to the necessary degree of thinness, and 
proceed as before recommended with teeth. The “ sharpen- 
ing ” stone will remove all scratches and marks sufficiently 
to allow it to be examined with the microscope to see if it is 
ground thin enough; and if it is to be mounted dry we must 
polish it with putty-powder and water upon the strop to as 
high a degree as possible, and having washed all remains of 
polishing powder, &c., from the section we must place it 
upon the slide and finish it as described in Chapter III. 
But where these sections are required for mounting in 
balsam a less amount of polish is necessary; thus.rendering 
the whole process much more readily completed. 
