PREPARATION, MOUNTING, AND COLLECTION OF OBJECTS. 175 



CHAPTER V. 

 PREPARATION, MOUNTING, AND COLLECTION OF OBJECTS. 



164. UNDER this head it is intended to give an account of those 

 Materials, Instruments, and Appliances of various kinds, which have been 

 found most serviceable to Microscopists engaged in general Biological re- 

 search, and to describe the most approved methods of employing them 

 in the preparation and mounting of Objects, for the display of the 

 minute structures thus brought to our knowledge. Not only is it of the 

 greatest advantage that the discoveries made by Microscopic research 

 should as far as possible be embodied (so to speak) in ' preparations/ 

 which shall enable them to be studied by every one who may desire to do 

 so; but it is now universally admitted that such ' preparations ' often 

 show so much more than can be seen in the fresh organism, that no ex- 

 amination of it can be considered as complete, in whicli the. methods most 

 suitable to each particular case have not been put in practice. It must 

 be obvious that in a comprehensive Treatise like the present, such a gen- 

 eral treatment of this subject is all that can be attempted, excepting in a 

 few instances of peculiar interest. And as the Histological student can 

 find all the guidance he needs in the numerous Manuals now prepared 

 for his instruction, the Author will not feel it requisite to furnish him 

 with the special directions that are readily accessible to him elsewhere. 



SECTION" 1. Materials, Instruments, and Appliances. 



165. Glass Slides. The kind of Glass best suited for mounting ob- 

 jects, is that which is known as ' patent plate;' and it is now almost 

 invariably cut, by the common consent of Microscopists in this country, 

 into slips measuring 3 in. by 1 inch. For objects too large to be mounted 

 on these, the size of 3 in. by 1-J in. may be adopted. Such slips may be 

 purchased, accurately cut to size, and ground at* the edges, for so little 

 more than the cost of the glass, that few persons to whom time is an ob- 

 ject, would trouble themselves to prepare them; it being only when glass 

 slides of some unusual dimensions are required, or when it is desired to 

 construct 'built-up cells' ( 174), that a facility in cutting glass with a 

 glazier's diamond becomes useful. The glass slides prepared for use 

 should be free from veins, air-bubbles, or other flaws, at least in the cen- 

 tral part on which the object is placed; and any whose defects render 

 them unsuitable for ordinary purposes, should be selected and laid aside for 

 uses to which the working Microscopist will find no difficulty in putting 

 them. As the slips vary considerably in thickness, it will be advantage- 

 ous to separate the thin and the thick from those of medium substance. 

 The first may be employed for mounting delicate objects to be viewed 



