102 COLLODION AND OTHER IMBEDDING METHODS. 



vulcanite known as " Stabilit," which is manufactured for electrical 

 insulation purposes. It is supplied in suitable blocks by JUNG, and 

 by GKUBLEK. Wood is liable to swell in alcohol so that it no longer 

 fits into the object-holder. BABCOCK (Journ. R. Micr. Soc., 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 recommends that the 

 knife be smeared with yellow vaseline ; it cuts better, is protected 

 from 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 rem'ove the mass before staining, as it usually 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. 

 You may mount in balsam, also, without removing the mass, 

 which does no harm, and serves the useful purpose of holding the 

 parts of the sections together during the manipulations. Dehydrate 

 in alcohol of 95 or 96 per cent, (not absolute, as this attacks the 

 collodion). NIKIFOROW (Zeit. wiss. Mik., viii, 1891, p. 189) recom- 

 mends a mixture of equal parts of alcohol and chloroform. Clear 

 with a substance that does not dissolve collodion. The clearing 

 agents most recommended are origanum oil (01. Origan. Cretici, it 

 is said, should be taken, not 01. Orig. Gallici ; but see as to this 

 reagent the remarks in 125), bergamot oil (said to make sections 

 shrink somewhat), oil of sandal-wood, lavender oil, oil of cedar- wood 

 (safe and gives excellent results, but acts rather slowly), chloroform, 

 xylol, or benzol (may make sections shrink if not well dehydrated), 



