626 



METHODS AND FORMULAS 



S 22-S 31 



22 PHYSICAL PROPERTIES OF SYNTHETIC CLEARING AGENTS— 



{Continued) 



* These materials are not 

 ethanol. A 50-50 mixture of 



in themselves solvents of nitrocellulose but are excellent cosolvents when mixed with 

 the solvent with ethanol is usually employed. 



S 30 Universal Solvents 



These materials are coming more and 

 more into favor as a means of avoiding the 

 use of two solutions, either before mount- 

 ing in resinous media or embedding in 

 wax. Though they are undoubtedly suit- 

 able for routine procedures, the writer 

 prefers not to employ them for deUcate 

 objects, particularly those containing 

 cavities which may become distorted 

 through heavy diffusion currents and 



osmotic differences. The danger in the use 

 of these materials hes both in the original 

 transfer from water into them and in the 

 transfer from them to paraffin. Unless 

 time is the essence of the technique em- 

 ployed, it is recommended that dehydra- 

 tion be conducted with mixtures of these 

 solvents with water and that the transfer 

 to wax be through graded mixtures of 

 solvent with wax. 



31 PHYSICAL PROPERTIES OF UNIVERSAL SOLVENTS 



Name 



Acetic acid 

 Butanol 



Cresol 



Diacetone 

 alcohol 



Diethylene 

 dioxide 



Diethylene 

 glycol 

 mono- 

 butyl 

 ether 



Other 

 names 



n-butyl 

 ale, pro- 

 pyl carbi- 

 nol 



diace- 

 tone 

 dioxane 



butyl 

 carbitol 



Re- 

 frac- 

 tive 

 index 



BoU- 



ing 

 point 



1.37 118 



Evapo- 

 ration 

 rate 

 (ethanol 

 = 100) 



? 



Solubil- 

 ity of 

 water 

 in 



Suit- 

 ability Misci- 

 • for use bility 

 with with 

 stained molten 

 materials paraffin 







Misci- 



bility 



with 



Canada 



balsam 



+ + + 



Solubil- 

 ity of 

 nitro- 

 cellu- 

 lose in 



1.34 



117.7 



180- 



200 



20% 

 50% 



+ + 

 



00 



00 



00 



00 



* 







1.30 169 



1.42 101.5 



+ + 



+ + + 



230.4 <0.1 



+ 



+ + + 



