METHOD OF CUTTING SECTIONS. 145 



the point of the pin is stuck through the bottom of 

 the mould into the cork in such a way that the 

 tissue is placed at one end of the oblong, and sus- 

 tained in a horizontal position about half way down 

 in the embedding trough, as shown in Fig. 23. All 

 is done as quickly as possible, so as not to allow the 

 tissue time to become too dry (if there is any fear of 

 this it must be moistened now and then with a drop of 

 spirit), and without manipulating the piece more than 

 can possibly be helped. The object to be cut being 

 thus fixed in the proper position, melted wax-mass 

 is poured into the mould so as to fill it completely, 

 and entirely to surround the piece of tissue, and the 

 mould is set aside to cool. It is important not to 

 use the mass hotter than just above its melting-point, 

 as the tissues, even when hardened, are liable to be 

 injured by too high a temperature. When the wax 

 is completely set the pin is carefully withdrawn and 

 the trough removed from the cork and placed in 

 spirit. Here the cooling is soon completed, and the 

 paper or capsule metal having been taken away the 

 embedded tissue is ready for cutting. 



Method of cutting the sections. The sections, 

 unless a microtome or section instrument is used, 

 when a special form of knife is often provided, are 

 made with an ordinary razor, the blade of which 

 should be somewhat hollow-ground on both surfaces. 

 Some prefer that the under surface should be ground 

 flat, and this is advantageous for large pieces of 

 tissue, but it is not so readily kept sharp. For this 

 last- mentioned purpose a good strop is absolutely 

 necessary. The razor is kept constantly wetted 

 during use with spirit, contained in a lar^e shallow 

 glass dish, into which the instrument is dipped from 

 time to time, and in which also the sections are in 

 the first instance placed. 



All then being ready, the cake of wax-mass (pro- 

 tected from the warm fingers by being wrapped 

 round with a small strip of bibulous paper) is held 

 in the left hand with the end in which the tissue 

 13 



