16 EMBEDDIKG MEDIA. 



away superfluous Alcohol ; the piece is then dipped in Muci- 

 lage, and finally frozen on the microtome in the usual way. 



(iv.) GLYCERINE GELATINE (Kleb's). 



Best Gelatine (French), 10 parts; wash and allow this to 

 stand in Distilled Water till it swells up : pour off excess of 

 Water, melt at a gentle heat, and add 1 parts of Glycerine, 

 and 2 p. c. of Carbolic Acid to preserve it. 



Method of Using. 



The tissue, which has previously been well washed with 

 Water to remove Alcohol, is saturated with the melted 

 Glycerine Jelly, which is then allowed to set. This may now 

 be frozen between pieces of carrot on the microtome by means 

 of Gum ; or it may be clamped between carrot for cutting. 



This method is useful for flat structures, such as the walls 

 of hollow organs, or membranes. 



(v.) PARAFFIN. 



Paraffin melting at between 45 0. (113F.) and 50 0. 

 (122 F.) according to the temperature of the room, and the 

 nature of the material to be cut. 



This medium is best adapted for embedding tissues that 

 have been stained in bulk. 



Method of Using. 



Some tissues are embedded in Paraffin, or other suitable sub- 

 stance, only as a means of holding them in the microtome ; 

 other tissues which are very porous or brittle require to be 

 saturated with the embedding material to hold the parts to- 

 gether during or after the cutting. 



Embedding. The tissue which has been dehydrated is dipped 

 for a second or two into melted Paraffin, and taken out again. 

 This gives the piece a coating of Paraffin. The tissue may 



