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Z\K riDicroscope an^ Ibow to 'ITlec it. 



By V. A. Latham, F.M.S. 



Part XII. — Section-Cutting. 



IT is of the utmost importance that the student should tho- 

 rouglily master the details of cutting sections by hand and 

 also with the aid of the microtome. For convenience we 

 will divide section-cutting into two classes, viz. — (i) Methods of 

 cutting by hand ; (2) with the microtome. 



TJnhardened Tissues. — If it be desirable to examine only a 

 small piece, snip off a thin fragment with a pair of scissors curved 

 on the flat, or cut off a slice with a Valentine's knife. 



Hardened Tissues.— If the piece of tissue be large enough, 

 hold it between the index-finger and thumb of the left hand, take 

 the razor firmly in the right, with the fingers closed above the 

 handle, support the back of the razor on the index-finger of the 

 former, and keep the handle in a line with the blade, cut from /(// 

 fo r/g/i^ and from heel to tip through the tissue towards yourself . 

 Be sure the razor is very sharp and keep the blade well wetted 

 with spirit, into which also the cut specimens must be floated off 

 with a camel's hair brush after each sweep of the razor, unless the 

 specimen has been already stained and dehydrated, in which case 

 clove-oil is to be used instead of the spirit for wetting the razor. 



The army razor is all that is required for ordinary use, and 

 should always be stropped in one direction. If the tissue is too 

 small or delicate to hold in the hand, it must either be clamped 

 or embedded in some substance. 



{a) Place the tissue to be cut between two pieces of amyloid or 

 waxy liver, or in the liver of a pig hardened in alcohol, hold 

 tightly between the finger and thumb, and cut with a razor in the 

 above manner. 



(/') Carrot, turni]~), potato, or elder pith may be used instead of 

 liver. Make a slit in the carrot, and clamp the tissue in it. The 

 usual way, however, is to embed the specimen in a wax mass or 

 some other mixture. 



