444 APPENDIX 



Miiller's fluid containing 5% of corrosive sublimate. It also contains 5% of glacial 

 acetic acid, which latter is only added just before we are ready to fix the piece of 

 tissue. Muller's fluid is: 



Pot. bichromate, 2 . 5 grams. 



Sod. sulphate, i . o grams. 



Water, loo.oc.c. 



Zenker's fluid fixes in about twenty-four hours. After all corrosive sublima 

 fixatives we should wash the tissues in running water for twelve to twenty-four 

 hours. The precipitate of mercury in the tissues is best gotten rid of by treating the 

 section on the slide with Lugol's solution, rather than the tissue in bulk with iodine 

 alcohol. 



(3) In Orth's fluid we add 10% of formalin to Muller's fluid (recommended for 

 nerve tissue). 



A saturated corrosive sublimate solution in salt solution with the addition of 5% 

 of glacial acetic acid may be used as a substitute for Zenker's fluid. 



(4) Where the tissue is to be examined chiefly for bacteria absolute alcohol is the 

 best fixative. The piece of tissue should be small, not over ^ inch thick and sus- 

 pended by a string to the cork so as not to lie on the bottom where the alcoholic 

 strength tends to become weaker. Better histological details are gotten by fixing 

 for two hours with 80% alcohol and then transferring to absolute for twelve to 

 twenty-four hours. 



2. Dehydration. After washing for twelve to twenty-four hours in running 

 water, following corrosive sublimate fixation, or simply washing for a few minutes 

 after formalin, the tissues should be placed in 70% alcohol. They may be kept in 

 this indefinitely. If they are to be sent to a laboratory for sectioning, it is advisable 

 to moisten a pledget of cotton in 70% alcohol and fill in the bottom of the bottle 

 with it. Then drop in the tissues and pack in gently over them sufficient 70% 

 alcohol-saturated cotton to fill up the bottle. All the alcohol should be absorbed 

 by the cotton so that if the bottle should break in transit there would be no damage 

 from the alcohol. The stopper of the bottle should be paraffined or sealed with 

 wax. 



Tissues may be left in the 70% alcohol twelve to twenty-four hours and should 

 then be transferred to 95% alcohol for an equal time. They are then transferred to 

 absolute alcohol, where they remain from two to twelve hours and are then placed in 

 xylol. The time in xylol should be as short as possible. So soon as the tissue looks 

 clear it should be removed thirty minutes to two hours. 



Bolles Lee is a strong advocate of the superiority of cedar oil over xylol or any other 

 clearing agent for paraffin imbedding. It does not affect delicate structures nor make 

 them brittle even when kept in the cedar oil for weeks or months. Furthermore, 

 it does not matter whether the cedar oil is entirely gotten rid of before sectioning the 

 paraffin as is the case for best results with xylol. Cedar oil will clear from 95% 

 alcohol as well as from absolute alcohol. 



3. Imbedding. The tissue is now transferred to melted paraffin. Paraffin melt- 

 ing at 48C. for winter work, and that melting at 54C. for summer is to be recom- 

 mended. The time in the paraffin should not be prolonged. Two hours will 

 ordinarily suffice. Some leave in the paraffin for twelve to twenty-four hours. 



