STAINING 757 



rapidly through absolute alcohol and xylol, and mount in balsam. The 

 sections may also be mounted directly from !)."> per cent, alcohol in 

 euparal. 



Mitochondria! Technics. Mitochondria (chondriosomes, plasto- 

 somes) are readily destroyed by acids, hence these must be eliminated 

 from fixing solutions, or greatly reduced. 



I. MEVES' METHOD. This is thesimplest method for demonstrating 

 mitochondria, and in many instances it is quite satisfactory. 



Very small pieces of tissue are fixed for eight days in Flemming's 

 strong solution in which the acetic acid has been reduced to 3 or 4 drops 

 in the simplest formula (see page 728). The tissue is then embedded 

 in paraffin in the usual way, and the sections cut at 3 to (>/* are stained 

 by the iron-hematoxyliu method. The nuclei and cytoplasm are a uni- 

 form pale gray; the mitochondria appear as deep black granules, rods 

 or filaments. 



II. BENDA'S METHOD. This is a more complicated technic, but 

 gives excellent results. 



1. Fixation in strong Flemming's fluid (acetic acid reduced to 



3 drops) for eight days. 



2. Wash in water one hour. 



3. Place in a mixture of equal parts of pyroligneous acid and 1 



per cent, chromic acid for twenty-four hours. 



4. Transfer to a 2 per cent, solution of potassium bichromate for 



twenty-four hours. 



5. Wash, dehydrate and embed in paraffin and fix on slide in the 



usual way. 



6. Mordant sections on slide in 4 per cent, solution of ferric 



alum for twenty-four hours. 



7. Rinse with water, and place in an amber-yellow aqueous solu- 



tion of Kahlbaum's suphalizarinate of soda (prepared by 

 dropping 1 c.c. saturated alcoholic solution in 100 c.c. of 

 water) for twenty-four hours. 



8. Rinse with water, flood slides with a solution of crystal violet 



(1 vol. sat. sol. of dye in 70 per cent, ale.; 1 vol. 1 per cent. 

 HC1 in 70 per cent, ale.; 2 vols. anilin water) and warm 

 until vapor is given off. 



9. Rinse, differentiate one or two minutes in 30 per cent, acetic 



acid solution. 

 10. Wash in running water five to ten minutes. 



