GENERAL DIRECTIONS. 23 



flame while the bulb is still hot ; they are thus made 

 absolutely dust-tight and may be kept always ready 

 for use, it being only necessary to break off the 

 sealed ends when required and to suck the reagent 

 up into the bulb. A pipette should always be re- 

 jected after it has once been used, and never em- 

 ployed for another reagent. 



For keeping preparations that have been per- 

 manently mounted, it is desirable to have a box or 

 cabinet in which the slides can be put away in a 

 horizontal position. 



General directions for work. Before com- 

 mencing see that the table is in order and clean, 

 and that everything is at hand that is usually 

 wanted for histological work. Especially look care- 

 fully to the glasses of the microscope that there is 

 no dust or other impurity on them. If any glyce- 

 rine or Canada balsam should have found its way 

 on to the objective, as is often the case when suffi- 

 cient care is not taken in placing a preparation 

 upon or removing it from the stage, they are to be 

 rubbed off, the former by a cloth wetted with water, 

 the latter with a little spirit. Before beginning to 

 prepare a tissue it will be necessary to look over the 

 description of the mode of making each preparation, 

 in order to know what vessels and what reagents to 

 get together. Otherwise many a specimen will be 

 spoiled by being left too long in one fluid whilst the 

 one to which it should be transferred is being got 

 ready. The cover-glass should always be cleaned 

 and dried before commencing, and placed ready to 

 hand in some situation where it is not likely to get 

 broken. It is well always to put the cleaned cover- 

 glasses in the same place say, on the foot of the 

 microscope otherwise, when wanted in a hurry it 

 is often difficult to find them at once. 



Every specimen that is to be kept must be dis- 

 tinctively labelled as soon as made ; and if there is 

 anything of importance to remember about it this 

 must be at once entered in" the notebook, which no 



