OF MICROSCOPIC OBJECTS. 151 
method of cutting wood is considered. To aid us in this 
- when the horn is hard it must be boiled for a short time in 
water, after which the cutting will be more easily affected. 
The sections should be both transverse and longitudinal, 
those of the former often showing cells with beautiful crosses, 
the colours with the selenite plate being truly splendid. Of 
this class the rhinoceros horn is one of the best; but the 
buffalo also affords a very handsome object. The cow’s, and 
indeed almost every different kind of horn, well deserves the 
trouble of mounting. Whalebone, when cut transversely, 
strongly resembles those of the third and softer formation. 
All these are best seen when mounted in Canada balsam, 
but care must be taken that they have been thoroughly dried 
after cutting, and then steeped in turpentine. 
An interesting object may 2lso be procured from whale- 
bone by cutting long sections of the hairs of which it is 
composed. Down the centre of each hair we shall find a 
line of cells divided from one another very distinctly. And 
(as recommended in the Micrographie Dictionary) if 
whalebone be macerated twenty-four hours in a solution of 
' caustic potash it will be softened, and by afterwards digest- 
ing in water, the outer part will be resolved into numerous 
transparent cells, which will show more plainly the structure 
of this curious substance. 
An object which frequently comes to the hand of any 
man who moves about in the world is a porcupine quill. 
This is a really valuable object for the microscopist. Trans- 
verse and longitudinal sections possess their respective 
beauty; and their appearance varies somewhat as to the 
distance from the point at which the section is made. 
Soaking in hot water for ashort time renders it easy enough 
to cut, and when dry and mounted in balsam the student is 
well repaid. 
In a former chapter, hairs were mentioned, their many 
and interesting forms, and their beauty when used with 
polarized light. The sections of them, however, are no less 
a matter of study, as this mode of treatment opens to sight 
