E 22.1-E 24.1 EMBEDDING MEDIA G49 



22.1 Wolf 1939 23632, 56:57 



method: [ol\iect, washed free of fixative] -^ laboratory glycerol, G hrs. —> anhydrous 

 glycerol, 6 hrs. — > wipe free frt)in glycerol — ^ suspend in 8% cclloidin, 2 days — > [make 

 block] 



23 RESINOUS MEDIA 



Resinous media, as has been explained in Chapter 10, are used for supporting mate- 

 rials from which sections are to be ground rather tlian cut. No specific mixtures have 

 been recommended for this puri)osc, though Canada balsam, damar, and ordinary resin 

 have all been employed. The only formula at present occupying this section is designed 

 to permit cutting thin sections in a polymerized resin, instead of a material hardened by 

 evaporation, as are the nitrocelluloses of the last section. 



23.1 Formulas 



23.1 Bourdon 1943 4285a, 20:40 



preparation: Catalyze vinyl acetate with 3% benzoyl peroxide and warm till syrupy. 

 Embed in this material impregnated, after dioxane dehydration, with vinyl acetate. 

 Polymerize at 37°C. for 48 hours followed by 48 hours at 56°C. Cut as though the block 

 were made of nitrocellulose. Sections of 2 /i-3 fj. may be obtained. 



24 OTHER MEDIA 



Three media, which cannot justifiably be included in either of the previous divisions, are 

 given under this heading. 



24.1 Formulas 



24.1 Barlow 1938 test. 1938 "A.B." Microscope, 2:150 



formula: paraffin (43°C.) 45, ethyl cellulose (low viscosity) 10, stearic acid 15 



24.1 Brain 1950 11360, 70:313 



stock solutions: I. 1% celloidin in 98% ale; II. 1% celloidin in abs. ale; III. 2.5% cel- 

 loidin in methyl salicylate 



note: Stock solutions I and II are prepared by dilution from a 30% solution of celloidin 

 in the usual 50:50 alc.-ether mixture. 



reagents required: A. 2% gelatin; B. 10% gelatin; C. AF 21.1 Brain 1950; D. stock I; 

 E. stock II; F. 60 stock II, 30 stock III; G. 50 stock II, 50 stock III; H. 30 stock II, 

 60 stock III; /. stock III; /. benzene; K. 60 benzene, 30 paraffin; L. 50 benzene, 50 

 paraffin; M. 30 benzene, 60 paraffin; TV. paraffin 56°MP 



method: [well-washed, formaldehyde-fixed material] -^ A, 4 days, 37°C. -* B, few hrs. 

 37°C. —f [cast in block of B] — ^ C, changed daily, until decalcification complete (45 

 days for mouse jaws) -^ running water, 24 hrs. -^50% ale, 30 mins., 37°C. -^70% 

 ale, 30 mins., 37°C. -^ 90% ale, 30 mins., 37°C. -* D, Ui hrs., 37°C. -^ E,3 changes, 

 each 30 mins., 37°C. -^ F, 1 hr., 37°C. -^ G, 1 hr., 37°C. -> H, 1 hr., 37°C. -^ /, 4 

 days, 37°C. ^ J,2 changes each 2^ hrs., 37°C. -^ K, 1 hr., 45''C. -^ L, 1 hr., 45°C. -> 

 M, 1 hr., 45°C. -* A'', 3 changes each 8 hrs., 58°C. -^ [cast block in N] 



recommended for: teeth, particularly for showing relation of enamel to dentine. 



24.1 Cutler 1935 1887a, 20:445 



method : glycol stearate used as paraffin but embedding from 95 % ale. 



