SECTIONING 



737 



celloidin sections and may also be used for small paraffin sections. The 

 Minot and the new Spencer rotary microtomes are specially adapted for 

 the production of serial sections in paraffin. These instruments of them- 

 selves suggest the manner in which they are to be used, and the technic 

 is easily acquired. Like all delicate instruments, they must be kept well 

 cleaned and properly oiled, to do good service. 



Much depends upon the choice and care of the knife. The micro- 

 c I d 



A 



b' 



c' 



d' 



D 



II 



/' e' f e/ 



FIG. 594. A METHOD OF PREPARING A PAPER Box FOR PARAFFIN EMBEDDING. 



7. A slip of paper, A, B, D, C, is folded, both ways, on the lines a-a', b-b f , c-c', 

 and d-d'. Then being folded into the form shown in //, it is laid flat, the section 

 o, a', b f , 6, shown in 7, being uppermost, and the paper is creased on the lines e-e' 

 and /-/'. It is then opened, folded in the shape of a box, /, e, /', e', forming the bot- 

 tom, and is secured by folding down the ends after creasing the paper on the lines 

 e-f and f-e'. 



tome knives of Jung are of excellent quality and should be kept in good 

 condition by the frequent use of the hone and strop. 



The h one should be of fine Belgian stone. It should be well moist- 

 ened with water, the addition of a little fine soap being a distinct ad- 

 vantage. The edge of the knife, carefully applied to the hone, should 

 first be drawn obliquely from heel to toe and toward the operator, being 

 held at a constant angle and drawn the whole length of the stone. The 

 knife is then turned over and the motion is reversed, the knife being 

 held obliquely at an angle equal to the previous one, the edge directed 



