11.0 CHAPTER I A. 



cork for mounting on the microtome, if the object-holder be 

 a vice ; for cork bends under the pressure of the holder, and 

 the elastic collodion bends with it, deforming the object. If 

 the object-holder be of the cylinder type, a good cork may 

 be used ; but even then, I think, wood is safer. Gage has 

 recommended bits of glass cylinders. Jelinek [Zeit. u-is-s. 

 Mile, 11, 1894, p. 237) recommends a sort of vulcanite 

 known as " Stabilit," which is manufactured for electrical 

 insulation purposes. It is supplied in suitable blocks by 

 Jung, and by Geijblee. Wood is liable to swell in alcohol 

 so that it no longer iits into the object-holder. Babcock 

 {Journ. R. Micr. 8oc., 1901, p. 339) uses a block of hard 

 paraffin, with the surface corrugated. 



Sections (from such masses as have not been cleared before 

 cutting) are cut with a knife kept abundantly wetted with 

 alcohol (of 50 to 85 or even 95 per cent.). Apathy recom- 

 mends that the knife be smeared with yellow vaseline; it 

 cuts better, is protected fi'om the alcohol, and the mobility 

 of the alcohol on the blade is lessened. 



The knife is set in as oblique a position as possible. 



Very brittle sections may be collodionised as explained 

 § 147. 



The sections are either brought into alcohol (of 50 to 85 

 or 95 per cent.) as fast as they are made, or if it be desired 

 to mount them in series, they are treated according to one of 

 the methods described below, in Chapter X. 



Masses that have been cleared before cutting with cedar 

 oil or the like may be cut dry, § 170. 



166- Staining — The sections may now be stained as desired, 

 either loose, or mounted in series on slides or on paper as 

 described in Chapter X, It is not in general necessary, nor 

 indeed desirable, to remove the mass before staining, as it 

 usu.ally either remains colourless, or gives up the stain on 

 treatment with alcohol. But if it be desired, the mass may 

 be removed by treating the sections with absolute alcohol or 

 ether. 



167. Clearing and Mounting. — You may mount in glycerin 

 without removing the mass, which remains as clear as glass 

 in that medium. 



