CH.IX] PREPARATION OF REAGENTS 283 



When the second coat is dry, sand paper the wood and dust off the excess 

 chemicals. Then wash the wood well with water. When dry, sand paper the 

 surface and then rub thoroughly with a mixture of equal parts turpentine and 

 linseed oil. The wood may appear a dirty green at first but it will soon 

 become ebony black. If the excess chemicals are not removed the table will 

 crock. An occasional rubbing with linseed oil and turpentine or with turpen- 

 tine alone will clean the surface. This is sometimes called the Danish method, 

 Denmark black or finish. See Jour. Ap. Micr., Vol. I, p. 145 ; Bot. Zeit, Vol. 

 54, p. 326, Bot. Gazette, Vol. 24, p. 66, Dr. P. A. Fish, Jour. Ap. Micr. , Vol. 

 VI., pp. 211-212. 



\ 429. Zenker's Fluid.— Miiller's Fluid, ((S 418), 100 cc. ; mercuric 

 chlorid 5 grams. Just before using add 5 cc. of glacial acetic acid to each 

 100 cc. of the above. Fix fresh tissue 5 to 24 hours. Wash out with running 

 water 24 hours. Then place in 67% alcohol 1 day or more and finally preserve 

 in 82% alcohol. Tissue fixed in Zenker's has mercuric crystals. They may 

 be removed from the tissue by long treatment with iodin, or by putting the 

 slide bearing the sections in iodized alcohol for half an hour or more (§ 413). 



This is an excellent fixer, combining the good qualities of mercuric chlorid 

 and of the chromium compounds. Tissues fixed with this show well the red 

 blood corpuscles. 



REFERENCES FOR CHAPTER IX 



For information concerning this chapter the reader is first of all advised 

 to consult the microscopical periodicals, especially the Journal of the Royal 

 Microscopical Society and the Zeitschrift fiir wissenschaftliche Mikroskopie 

 und fiir mikroskopische Technik. The smaller journals and the proceedings 

 of microscopical societies frequently have excellent articles bearing upon the 

 subjects of this chapter. This is especially true of the Journal of Applied 

 Microscopy and Laboratory Methods, and the Transactions of the American 

 Microscopical Society. 



Among modern books, Lee's Microtomists' Vade Mecum, Mann's Physio- 

 logical Histology and Ehrlich's Encyclopaedic der mikroskopischen Technik 

 are indispensable in a laboratory. For the history of staining see Mann. 

 pp. 190-195. • 



