INSTRUMENTS FOR MICROSCOPIC DISSECTION. 187 



Scissors, curved to one side, is extremely convenient for cutting open 

 tubular parts ; these should have their points blunted ; but other 

 scissors should have fine points. A pair of very fine-pointed 

 Scissors (Fig. 92), one leg of which is fixed in a light handle, and the 

 other kept apart from it by a spring, so as to close by the pres- 

 sure of the finger and to open of itself, "will be found (if the blades 

 be well sharpened on a hone) much superior to any kind of knives, 

 for cutting through delicate tissues with as little disturbance of 



Fig. 92. 



Spring-Scissors. 



them as possible : Swammerdam is said to have made great use of 

 this instrument in his elaborate Insect dissections. Another cut- 

 ting instrument much used by some dissectors may be designated 

 as a miniature of the shears used in shearing sheep, or as a cutting- 

 forceps ; the blades of such an instrument may be prevented from 

 springing too far asunder by means of a regulating-screw (as in the 

 Microtome of M. Strauss-Durckheim), or by some other kind of 

 check; and the cutting action, being executed by the opposed 

 pressure of the finger and thumb, may be performed with great 

 precision. A pair of small straight Forceps with fine points, and 

 another pair of curved forceps, will be found useful in addition to 

 the ordinary dissecting forceps. — Of all the instruments contrived 

 for delicate dissections, however, none are more serviceable than 

 those which the Microscopist may make for himself out of ordinary 

 Needles. These should be fixed in light wooden handles* (the cedar 

 sticks used for camel-hair pencils, or the handles of steel-penholders, 

 or small Porcupine -quills, will answer extremely well), in such a 

 manner that their points should not project far,f since they will 



* Special Needle-Holders (like miniature port-crayons) have been made 

 for this purpose ; and although they afford the facility of lengthening 

 or shortening the acting point of the needle at will, and also of carrying 

 a reserve store of needles at the other end, yet the Author would de- 

 cidedly recommend the use of the wooden handles, of which a large 

 stock may be obtained for the cost of a single pair of special Holders. 



t The following is the mode in which the Author has found it con- 

 venient to mount his Needles for this and other purposes : — the needle 

 being held firmly in a pair of pliers grasped by the right hand, its point 

 may be forced into the end of a cedar or other stick held in the left, 

 until it has entered to the depth of half an inch or more ; the needle is 

 then cut off to the desired length (the eye-end being thus got-rid-of) ; 

 and being then drawn out, the truncated end is forced into the hole 

 previously made by the point, until it cannot be made to penetrate 

 farther, when it will be found to be very securely fixed. The end of 

 the handle which embraces it may then be bevelled-away round its point 

 of insertion. 



