OF MICROSCOPIC OBJECTS. 17 



Many objects for the microscope may be seriously injured by 

 allowing the fingers to touch them many more are so minute 

 that they cannot be removed in this way at all, and often it is 

 necessary to take from a mass of small grains, as in sand, some 

 particular particle. To accomplish this, there are two or three 

 contrivances recommended : one by means of split bristles, many 

 of which will readily be found in any shaving brush when it has 

 been well used. The bristles when pressed upon any hard surface 

 open, and when the pressure is removed close again with a spring ; 

 but the use of these is limited. Camel-hair pencils are of great 

 service for this and many other purposes to the microscopist. 

 In very fine work they are sometimes* required so small that all 

 the hairs with the exception of one or two finer pointed ones are 

 removed. A few of various sizes should always be kept on hand. 



Equally necessary are fine pointed needles. They are very 

 readily put up for use by thrusting the " eye" end into a common 

 penholder, so as to be firm. The points may be readily renewed, 

 when injured, on a common whetstone ; but when out of use 

 they may be protected by being thrust into a piece of cork. 



Knives of various kinds are required in some branches of 

 microscopic work, but these will be described where " dissection," 

 &c., is treated at some length, as also various forms of scissors. 

 In the most simple objects, however, scissors of the usual kind 

 are necessary. Two or three sizes should always be kept on 

 hand, sharp and in good order. 



A set of glass tubes, kept in a case of some sort to prevent 

 breakage, should form part of our "fittings" and be always 

 cleaned immediately after use. These are generally from six to 

 ten inches long and from one-eighth to a quarter of an inch in 

 diameter. One of these should be straight and equal in width at 

 both ends ; one should be drawn out gradually to a fine point ; 

 another should be pointed as the last, but be slightly curved at 

 the compressed end, in order to reach points otherwise unattain- 

 able. It is well to have these tubes of various widths at the 

 points, as in some waters the finer would be inevitably stopped. 

 For other purposes the fine ones are very useful, especially in the 

 transfer of " preservative liquids," which will come under notice 

 in another chapter. 



3* 



