CH. AY] PREPARATION OF REAGENTS 273 



Berlin blue are more satisfactory and last longer with full brilliancy if the 

 balsam is made more acid than it naturally is. For this use 10 to 20 drops of 

 glacial acetic or formic acid to 100 cc. of balsam. 



\ 388. Borax Carmine for in Toto Staining. — Borax 4 grams ; Carmine 3 

 grams ; water 100 cc. Shake frequently for several days and then filter and 

 add 100 cc. of 67% alcohol. After 3 to 4 days it may be necessary to filter 

 again. Good for in toto staining after almost any fixer. Put the object to be 

 stained from alcohol into a vial with plenty of stain. After a day or two 

 change the stain. Stain 4 to 5 days. Remove to 67% alcohol adding 4 drops 

 of H CI to each 100 cc. of alcohol. After one day remove to 82% alcohol. 

 Change the alcohol till no more color comes away, then proceed to section. 

 Remember that objects stained in toto may be mounted directly in balsam 

 from de-paraffining xylene. 



\ 389. Carmine for Mucus (Mucicarmin). — One can buy the dry powder 

 or preferably prepare the stain. To prepare it take 1 gram of Carmine No. 40 

 and Yi gram of pure dry ammonium chlorid. If the latter is slightly moist, 

 dry it in an evaporating dish in a sand bath. Mix the ammonium chlorid and 

 the carmine and add 2 cc. of water. Mix well and heat over a sand bath, con- 

 stantly mixing with a glass rod. Continue the heating until the carmin col- 

 ored mass becomes very dark red. It will take 3 to 10 minutes for this. The 

 heat should not be too great. 



Dissolve the dark red mixture in 100 cc. of 50%' alcohol. For use, dilute 

 five or tenfold with tap water. This stains best after mercuric fixers. One 

 must not collodionize sections to be stained with this as the carmine stains the 

 collodion very deeply. Stain the sections first with hematoxylin as usual 

 then stain 1 to 5 hours or longer with the dilute mucicarmin. The mucus in 

 goblet cells, in the mucous part of the salivary glands, etc., will be red. 

 Nuclei will be stained with hematoxylin. Mount in balsam (§ 383). 



(J 390. Cedar-Wood Oil. — This is used for oil immersion objectives and is 

 quite thick. 



For penetrating tissues and preparing them for infiltration with paraffin, 

 thick oil is recommended by Lee. The writer has found, however, that any 

 good cedar- wood oil gives excellent results inordinary histologic and embry- 

 ologic work. That known as Cedar- Wood Oil (Florida) is excellent, also 

 that known as Cedar-Wood Oil (true Lebanon). These forms are far less- 

 expensive than that used for immersion objectives. The tissues should be 

 thoroughly dehydrated before putting them into cedar-wood oil, and they 

 should remain until they are translucent. 



\ 391. Clarifier, Castor-Xylene Clarifier. — This is composed of castor oil 1 

 part and xylene* 3 parts. (Trans. Amer. Micr. Soc, 1895, p. 361.) 



*The hydrocarbon, xylene (C S H 10 ) is called xylol in German. In English, 

 members of the hydrocarbon series have the termination " ene " while mem- 

 bers of the alcohol series terminate in " ol." 



