COLLECTION OF SPECIMENS 153 



sive instrument, though it is of course true that, 

 within certain limits, the better the implement 

 the better the results to be obtained by its use. 

 At the same time, it should be borne in mind that 

 a microscope is an instrument that consists of 

 many parts, and that divers of these may be added 

 and improved upon from time to time as occasion 

 offers. If possible, it is well to begin with a good 

 microscope stand (i.e. the body without accessories), 

 as this may be made the foundation on which to 

 gradually build up a more or less perfect whole. 

 My own experience would lead me to say that, 

 if the funds will allow, the binocular model is 

 greatly to be preferred to the monocular, if only on 

 account of the saving of strain to the eyes that is 

 thereby effected. Fortunately, in the examination 

 of mosses, the higher powers of magnification are 

 seldom or never requisite, which makes it unneces- 

 sary to obtain the more expensive lenses. As a 

 rule, I work with 2 -inch, 1-inch, and J-inch objec- 

 tives, with an occasional recourse to a J-inch glass 

 when some finer detail of cell-structure has to be 

 elucidated. To these may be added a 3-inch lens, 

 which is especially useful in the exhibition of 

 slides ; and in ordering the microscope-stand it 

 should be stipulated that the " racking out " should 

 be sufficient to accommodate so low a power as 

 this, in combination with a triple nose-piece. 



In order to prepare specimens for examination 

 or for mounting, some form of dissecting-micro- 



