DISSECTING INSTRUMENTS. 



349 



making them red hot in the flame of a spirit lamp, and after 

 tliey have been bent to the proper shape, they may be 



Fiff. 233. 



hardened again by heating them a second time, and dipping 

 them into cold water or tallow. The needles selected should 

 not be very long, as they are apt to be too springy; to prevent 

 this, they should not be allowed to project far beyond the 

 holder; their points may be ground very sharp, or be made 

 with a cutting edge like a scalpel, by means of a Turkey 

 stone. These instruments are sometimes employed for mount- 

 ing objects in balsam, as described at page 305 ; but a more 

 common kind wUl on the whole be quite as convenient^ and 

 less trouble wiU be required in keeping them clean.* 



Non-cutting Instruments. — Besides the instruments above 

 mentioned, many others wUl be found necessary for the pur- 

 poses of dissection; these consist principally of troughs or 

 vessels for holding the subjects to be dissected, of blocks of 

 wood for supporting the same, of corks loaded with lead, and 

 of supports for the arms and wrists, termed rests; pins of 

 various kinds, braces, a pair of pliers, an old scalpel or two, 

 and a small syringe will all be occasionally required. 



Troughs. — As most delicate dissections are conducted under 

 water, some form of vessel, made either of metal, earthenware, 

 or glass, should be employed. These may be of various sizes, 

 from a foot to two feet in length, and of a proportionate 

 breadth and depth, if made of metal, tin or zinc, well japanned, 

 may be used; the shape should be such that the bottom may 



* All the various kinds of cutting instruments employed for dissecting 

 may be obtained of Mr. Thomas Weedon, surgical instrument-maker, 

 No. 41, Hart-street, Bloomsbury, whose ingenuity, as displayed in their 

 construction, is so very well known. 



