SECTION ONE 



A. Absolute alcohol . . . . 210 ml. 



Ether . . . . . . . . 250 ml. 



Dibutyl phthalate . . . . 5 ml.* 



Mix well and add 140 gm. L.V.N, (as supplied 

 damped with N. butyl alcohol). 



* NOTE 



In the original paper (Chesterman and Leach, 1949) and in the previous 

 edition of this book (1953), tricresyl phosphate was stipulated: this has now been 

 replaced by dibutyl phthalate, and I am indebted to Professor F. Bergel of 

 The Chester Beatty Research Institute, Institute of Cancer Research, Royal 

 Cancer Hospital, London, for calling my attention to the potential danger of 

 handling tricresyl phosphate. Professor Bergel informs me that tricresyl-o- 

 phosphate is highly toxic, more than 7-30 mg./kg. producing severe paralysis, 

 and while the corresponding meta- and para-compounds show little sign of 

 having this toxicity, the tricresyl phosphates on the market, up to the present 

 time, always contain some of the ortho compound. 



References: Aldridge, W. N. (1954), Biochem.jf., 56, no. 2, 185-9, " Tricresyl 

 Phosphates and Cholinesterase". Thompson, R. H. S. (1954), Chem. and Ind., 

 749, Martindale's Extra Pharmac. (1941), vol. i, 200-1. 



B. Absolute alcohol . . . . 210 ml. 

 Ether . . . . . . . . 250 ml. 



Mix well and add 140 gm. L.V.N, (damped with 

 N. butyl alcohol). 



From Solution B prepare also 5% and 10% solutions by diluting 

 with a mixture consisting of equal parts of absolute alcohol and 

 ether. 



C. Xylol . . . . . . . . 2 parts 



Toluol . . . . . . . . I part 



Beechwood creosote . . . . i part 



Procedure for embedding tissues: 



1. Fix and dehydrate tissues as usual; then immerse in ether- 

 absolute alcohol (equal parts) for one day. 



2. Immerse in 5% L.V.N, for three to five days. 



3. Transfer to 10% L.V.N, for one to two days. 



4. Transfer to 20% L.V.N. (Solution B above) for one to five 

 days. 



5. Embed in Solution A. 



6. Allow to harden slowly in a desiccator. In one to five days 

 the block should be adequately hard. At this stage it should be a 



27 



