CHAPTER XXVI. 295 



647. Iodine Method. Fix tissue in Carnoy, or alcohol absolute, 

 4 parts, acetic acid glacial, 1 part ; or in absolute alcohol ; or in 

 alcoholic fixatives not containing alcohol lower than a strength of 

 90 per cent. It is better if the tissue is cut small. Fix for one hour, 

 then transfer for twenty-four hours or longer, in two changes of 

 absolute alcohol ; then xylol and paraffin wax. Fix sections to 

 slide with a mixture of 50 per cent, alcohol with a few drops of 

 glycerin and albumen, using the alcohol as you would water ; 

 drain the slides dry. Remove wax in xylol, bring to 70 per cent, 

 alcohol. Stain sections in Ehrlich's hsematoxylin for five or ten 

 minutes. Blue in tap water substitute, 669. Pass to a 2 per cent, 

 solution of potassium iodide saturated in iodine (a Lugol solution) ; 

 leave five minutes ; pour away, wipe around slide, and dehydrate 

 in absolute alcohol saturated in iodine. Clear in oleum origanum 

 cretici for about ten minutes. Mount in origanum balsam. Such 

 preparations should keep for years without fading much. I have 

 some slides of human placenta which after six years still show the 

 glycogen. 



648. BEST'S Carmine Stain. Material is fixed as for the iodine 

 method and may be imbedded in celloidin. If paraffin sections are 

 used the slide must be placed in 1 per cent, celloidin overnight, 

 drained and allowed to dry partly, and then plunged into chloroform 

 and absolute alcohol (equal parts), then treated as for celloidin 

 sections. Transfer through alcohols 90 per cent, and 70 per cent, 

 to water. Stain in Ehrlich's or iron hsematoxylin as usual, but 

 differentiate in acid alcohol. Then proceed to BEST'S carmine 

 stain (Zeit. f. mikros., Bd. xxiii). Make up this stock carmine 

 solution :- 



Carmine ....... 2 grms. 



Potass, carbonate . . . . .1 grm. 



Potass, chloride . . . . .5 grms. 



Aq. dest. . . . . . . .60 c.c. 



Boil gently for a few minutes ; cool. 



Add strong liq. ammon. 20 c.c. Keep this solution in a well- 

 stoppered bottle in a cupboard. It may go bad in a month during 

 summer. 



Wash sections in distilled water after staining in hsematoxylin. 

 Stain in following solution :- 



Stock carmine solution .... 2 parts. 



Liq. ammon. fort. . . . . 3 



Methyl alcohol (pure) . . . 3 



for five minutes. 



