INSTRUMENTS FOE MICROSCOPIC DISSECTION. 203 



compound Microscope is brought to bear upon it. Wbenevei'' a 

 dissection is being made upon tbe stage of a microscope, it is 

 desirable that support should be provided for the hands on either 

 side. This may be given by books or blocks of wood piled up 

 to the requisite height; but in place oi flat "rests," it is much 

 more convenient to provide a pair of inclined planes, sloping 

 away from the stage at an angle of about 30° below the horizon. 

 These may be either solid blocks of wood, or (which is much 

 less cumbrous) they may be made of two boards hinged together, 

 one giving the inclined plane, which rests at one end upon the 

 table, whue the other, standing vertically, affords the requisite 

 elevation to the extremity which abuts against the stage. 



105. The instruments used in Microscopic dissection, are for 

 the most part of the same kind as those which are needed in 

 ordinary minute Anatomical research, such as scalpels, scissors, 

 forceps, &c. ; the fine instruments used in operations upon the 

 eye, however, will commonly be found most suitable. A pair of 

 delicate 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 

 fine-pointed scissors (Fig. 56), one leg of which is fixed in a light 

 handle, and the other kept p^^ gg 



apart from it by a spring, so 

 as to close by the pressure of 

 the finger and to open of it- 

 self, will be found (if the 

 blades be well sharpened on spring-scissors. 



a hone) much superior to any 



kind of knives, for cutting through delicate tissues with as little 

 disturbance of them as possible : Swammerdam is said to have 

 made great use of this instrument in his elaborate insect-dissec- 

 tions. Another cutting 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-Purck- 

 heim) 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, how- 

 ever, none are more serviceable than those which the Microsco- 

 pist may make for himself out of ordinary needles. These should 

 be fixed in light wooden handles' (the cedar sticks used for 



' Special needle-holders (like miniature port-orayons) have been made for this pur- 

 pose; 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 decidedly recommend the use of the wooden handles, of which 

 a large stock may be obtained ibr a trifle. 



