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 also 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 Micrographic 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 conies 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 a short 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 



