Method III 2^ 



before, keep the fluid at or below a temperature of 20° C. for 

 6-12 hours. 



The tissue again becomes a light yellow or almost white. 



6. Again place in 96 per cent, alcohol for 10-12 hours. 



7. The tissue is now washed in a copious amount of dis- 

 tilled water for 2-6 hours. 



This step is inconsistent with the ordinary procedure. It 

 may be that the tissue is now so thoroughly hardened and the 

 elements so held in place by the various precipitates that it is 

 not injured by the action between the 96 per cent, alcohol 

 and the water, 



8. Molybdating.— Replace the water with 30-40 volumes of 

 the ammonium molybdate solution (E) for 24 hours. During 

 this period it is' rf^commended that a temperature even lower 

 than- before be maintained (10-15" C. ). 



A perceptible white precipitate is formed. 



9. Wash the pieces for 3-4 minutes in distilled water and 

 transfer again to 30-40 volumes of 96 per cent, alcohol for 6-10 

 hours. 



10. Complete the dehydration in 20-30 volumes of absolute 

 alcohol for 10-12 hours. 



The penetration of the alcohol and the infiltration of the 

 clearing oil and imbedding media to follow occur more slowly 

 than in case of tissues prepared in the ordinary way, and conse- 

 quently the tissue must be allowed more than the ordinary time 

 in each: 



11. Clear in about 10 volumes of xylol or toluol slightly 

 warmed (40° C), and occasionally agitated (see I, 3, note, p. 

 16) for 3-5 hours. It may be necessary to renew the clearing 

 oil. 



12. Imbed in paraffin (celloidin will not do !). 



(«) Transfer from clearing oil to melted soft paraffin (I, 4, 

 p. 16) for about 40 minutes. 



[b) Transfer to melted hard paraffin for i hour. 



(c) Imbed in labeled paper boxes and cool as directed in I, 4, 

 {c), {d), note, pi;. 



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