Dehydration for Embedding 27 



composition of solutions for an ideal dehydrating series. For critical 

 cytological work, follow Lang's miscibility curves (Lang, 1937) in 

 making up a series. The following series is a simplification that has 

 been found to give excellent results in histological and anatomical 

 work. 



Note that each of the first six grades consists of three ingredients. 

 The last two grades are anhydrous. Use new anhydrous butyl alcohol 

 for Nos. 7 and 8. After being used once, No. 8 may be used to make 

 up any of the first six grades. 



After an aqueous killing fluid, wash or rinse the tissues in water, 

 dehydrate in alcohol in the usual manner to 30%, then transfer to 

 the abo\e reagent 1 and follow the series. After FAA or other fluids 

 having a water content of about 50%, rinse in 2 changes of 50% 

 alcohol and begin the n-butly series with No. 2, in which the water 

 content is 60%. With many histological subjects good results can be 

 obtained by dehydrating to 50% in steps of 10%, then continuing in 

 n-butyl series 3, 5, 7, and 8. 



Tertiary butyl alcohol (TBA) is regarded by some workers as 

 the most ideal dehydrating reagent of any thus far used (Johansen 

 1940) . Unlike the two other butyl alcohols, its odor is agreeable. 

 The cost is at present much too high for extensive routine work. 

 Tertiary butyl alcohol is used in accordance with the principles of 

 dehydration described in the preceding pages. Dehydrate in ethyl 

 alcohol to 50%, then pass through the following series: 



