378 APPENDIX. 



The success of silver preparations largely depends upon 

 not dragging the tissue, on washing it well, and on 

 exposing it to a bright light. The reduction of the 

 silver may be hastened by placing it in dilute alcohol 

 instead of in water. 



The reduction of silver goes on though slowly in the 

 other parts of the tissue, so that it becomes darker 

 and darker, until it is useless ; this is rendered less 

 rapid by mounting. 



MOUNTING. 



The fluids in which tissues are mounted serve to make 

 them more transparent and to preserve them. 



Glycerine. 



It is best to allow sections to soak in glycerine for 

 5 10 minutes before mounting so that the glycerine 

 may thoroughly penetrate them. 



Some unstained tissues are made too transparent by 

 strong glycerine, these should be mounted in gly- 

 cerine diluted with one or two vols. of water. 



Many gold chloride and most carmine-stained specimens 

 are best mounted in glycerine containing 1 p. c k of 

 formic acid 1-16 Sp. Gr. (formic glycerine). 



Some hardened tissues, stained or unstained, may with 

 advantage be kept in glycerine instead of in alcohol ; 

 before sections are made the glycerine must be 

 extracted from the tissue with water or alcohol. 



Creosote and Turpentine. 



Add 1 part of creosote to 4 of turpentine, shake well 



