CUTTING. 201 



accidents will be less likely to happen, and a good cork may 

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



Sections are cut with a knife kept abundantly wetted with 

 alcohol (of 50 to 85 or even 95 per cent.). Some kind of 

 drip arrangement will be found very useful here. Apathy 

 recommends that the knife be smeared with yellow vaselin ; 

 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 

 above ( 282). 



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 the chapter on " Serial Section 

 Methods." 



The above process is the one that has been until lately the 

 usual one ; but some workers prefer not to cut in the wet 

 way with alcohol, as above described, but to clear before 

 cutting. BUMPUS (Amer. Natur., xxvi, 1892, p. 80 ; see Journ. 

 Roy. Mic. Soc., 1892, p. 438) advises clearing the mass, after 

 hardening in chloroform, with white oil of thyme or other 

 suitable clearing agent (see below, 305). After clearing, 

 the under surface of the block of mass is washed with ether, 

 and cemented with thick celloidin solution to a block of wood 

 for cutting in the manner described above, the whole being 

 thrown into chloroform for a few minutes to harden the joint. 

 The knife is wetted with the clearing oil, and the same oil is 

 employed for covering the exposed surface of the object after 

 each cut. Similar recommendations are made by EYCLESHEIMEE 

 (op. cit., pp. 354, 563), carbolic acid, or glycerin, or the 

 mixture given 305 being suggested for clearing. Professor 

 GILSON writes me that he has for some time past adopted the 

 practice of clearing before cutting with cedar oil, as described 

 above, 301. I have not had the opportunity of trying this 

 modification of the usual process. It certainly wears the 

 look of being, at least for objects that have been stained 

 before imbedding, distinctly an improvement. 



304. Staining. The sections may now be stained as desired, 

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



