OF THE MICROSCOPE. Ill 



-^parent connection with each other. The truth is, however, 

 that we should never deduce the form of vessels from sections 

 alone. In every case it is necessary to examine carefully dis- 

 sected preparations as well as sectioi 



The soft parts of animals and vegetables are frequently pre- 

 pared for examination by careful dissection, that is to say the 

 different parts are separated from each other, and freed from ex- 

 traneous matter by means of knives, scissors, forceps, needles, 

 camel hair pencils, etc. The knives used by the microscopist are 

 similar to the scalpels ordinarily employed by anatomists, but 

 smaller, and unless very finely tempered and well-sharpened, 

 they are worthless. The knives sent out with low priced micro- 

 scopes are in general the veriest trash, and the same is true of the 

 needles. There are three kinds of scissors which the microscop- 

 ist will find useful plain, straight scissors, elbow scissors, and 

 curved scissors. They must be small, sharp and well made. But 

 the most useful, as well as the simplest instruments for dissecting 

 are a pair of fceedles, or, rather, a needle and a very fine 

 spatula. The needles used are those ordinarily employed by 

 seamstresses; they should be fixed in a light wooden handle and 

 carefully polished. The latter is a most important point, for 

 it will be found that ordinary needles are too rough for deli- 

 cate work, as may be easily seen by examining them under the 

 microscope. For microscopical purposes needles are made 

 both straight and curved the latter being a very useful form. 

 In order to bend a needle, it must first be heated in the flame 

 of a candle, then bent by proper pliers, after which it must be 

 carefully re-tempered. There is little danger of getting it too 

 hard, provided it is not burned. After being hardened it must 

 be carefully re-polished. The handles should be light and 

 smooth. Ordinary penholders make good handles and cost but 

 a trifle, but in case of need any piece of straight-grained, light 

 wood will answer. Universal handles, handles with ferrules, 

 handles wound with thread, etc,, look as if they were not com- 

 mon articles, and are purchased by many, but no working mi- 

 croscopist would give them table-room. All the so-called uni- 

 versal handles in market are too clumsy and heavy. 



In using needles or knives for dissection, they are generally 

 used in pairs, that in the right hand being used for teasing or 



