312 APPENDIX 



Sections are placed in a watch-glass with a little of the 

 solution, warmed at about 20 to 25 C. till the fluid has nearly 

 evaporated. The sections are then placed in alcohol and moved 

 about, this rather rapidly removes the stain but much less 

 rapidly from the elastic tissue and the nuclei than from the rest 

 of the section ; the sections after dehydration are mounted in 

 balsam. If it is not convenient to mount at once, the sections 

 are washed with water and left in this. 



Films (cp. p. 74) which are only imperfectly hardened shrink 

 when warmed. They are best left for about two days in a few 

 c.c. of the following : 



80 c.c., 95 p.c. alcohol, 

 20 c.c. water, 



1 gram orcein, 



1 c.c. hydrochloric acid, 



washed with water and differentiated with acid alcohol. 



Sections may also be stained in this way. The optimum 

 quantity of hydrochloric acid varies with the hardening agent. 



