MILLIMICRON 



210 



MITOCHONDRIA 



0.01 cc. milk over area of 1-2 sq. cm. on 

 slide. Dry on flat warm surface 5 min. 

 Flood with stain 15 sec. Drain off ex- 

 cess and dry while flat with gentle heat. 

 Wash in cold water till all blue is re- 

 moved and a faint pink color appears. 

 Dry and examine. 



Technique for the rapid detection of 

 Mycobacterium tuberculosis in cows, 

 milk is described by Maitland, M. L. C, 

 J. Hyg., 1950, 48, 397-401. 



Millimicron (m^) = 1/lOOOth part of a 

 micron = 1/1, 000,000th part of a mm. = 

 10~' mm. = 0.001 micron = 10 A (see 

 Micromicron). 



Millon's Reaction. For microchemical pur- 

 poses it is necessary, as Bensley and 

 Gersh (R. R., and I., Anat. Rec, 

 1933, 57, 217-233) point out, for the 

 reagent to act without the aid of heat, 

 to give almost immediately with tyrosin 

 in vitro an intense red color yielding red 

 ppt. not changing to yellow within 24 

 hrs. They give the following directions. 

 Add 600 cc. aq. dest. to 400 cc. cone, 

 nitric acid (sp. gr. 1.42) making 40% by 

 volume. After 48 hrs. add 1 part to 9 

 parts aq. dest. Saturate with mercuric 

 nitrate crystals frequently shaking sev- 

 eral days. To make the reagent take 

 400 cc. filtrate, add 3 cc. original 40% 

 solution plus 1.4 gm. sodium nitrite. 

 Mount sections (preferably after freez- 

 ing and drying technique) to slides 

 without using water. Immerse in rea- 

 gent in cold. Maximum reaction should 

 be within 3 hrs. when sections show 

 noticeable rose color. However use 

 several slides, remove them from reagent 

 in a Coplin jar at intervals, dip imme- 

 diately in 1% aq. nitric acid, dehydrate 

 quickly in absolute alcohol, clear in 

 xylol and mount in balsam. Bensley 

 and Gersh found that mitochondria are 

 positive to Million's reagent. 



Mineral Oil, reactions in tissue to fat stains 

 after various fixations (Black, C. E., 

 J. Lab. & Clin. Med., 1937-38, 23, 

 1027-1036). See Immersion Oils. 



Mingazzini Phenomenon in intestinal villi 

 interpreted as an agonal or early post- 

 mortem change (by Macklin, C. C. and 

 M. T., J. Anat., 1926, 61, 144-150). 



Mites. The techniques given for Ticks and 

 Insects are applicable for making whole 

 mounts. The simple creosote method 

 (see Insects) is recommended. 



Mitochondria — Written by Geoffrey Bourne, 

 London Hospital Medical College, Lon- 

 don, England. November 5, 1951 — 

 Granules, rods and filaments existing 

 in the cj'toplasm of practically all liv- 

 ing cells of plants and animals. They 

 can be studied in living cells unstained 

 and after supravital staining, and in 

 fixed tissues. 



They can be seen in living cells even 

 with direct illumination if it is critical. 

 In mammals they probably are best 

 seen unstained in very small pieces of 

 pancreas mounted in normal saline and 

 flattened out by the pressure of the 

 cover glass. The distal poles of the 

 acinous cells, facing the glandular 

 lumen may be identified by densely 

 packed, highly refractile zymogen gran- 

 ules. The proximal poles are nearer 

 the surrounding blood vessels and com- 

 paratively free from zymogen granules. 

 With direct illumination a careful 

 search with an oil immersion objective 

 will distinguish the mitochondria as 

 delicate, slightly refractile filaments 

 oriented in general with their long axes 

 parallel with the length of the cell. 

 Wernicke illumination (phase contrast) 

 will permit immediate recognition of 

 these bodies which are shown up clearly 

 by this method. Phase contrast en- 

 ables mitochondria to be studied with 

 ease in a variety of living unstained 

 cells (H. U. Zollinger, Rev. d'Hematol., 

 1950,5,696). 



The clarity with which mitochondria 

 may be observed with phase contrast 

 in living unstained cells has rendered 

 their supravital staining less necessary. 

 However, on occasions, this may be 

 desirable. When very dilute methylene 

 blue is added to tissue culture cells the 

 mitochondria become stained a bril- 

 liant blue (Ludford, R. J., Arch. f. Exp. 

 Zellf., 1935, 17, 339-359). Other vital 

 dyes are diethylsafranin, Janus blue, 

 Janus black 1, Pinacyanol, Rhodamin 

 B. and Janus green B. (diethylsafra- 

 ninazo-dimethyl-analin chloride) . 



The latter is used, as an example, as 

 follows: 



Place a small drop of 1:10,000 Janus 

 Green B in 0.85% aq. sodium chloride, 

 dj^e should be added from a 1% stock 

 The solution in aq. dest. because the 

 power does not dissolve easily in salt so- 

 lution. In this drop a variety of small 

 pieces of tissue, may be teased, and then 

 covered with a cover glass, and mito- 

 chondria may be demonstrated very 

 beautifully in blood leucocytes by add- 

 ing a drop of freshly drawn blood to a 

 drop of 1 in 10,000 solution of Janus 

 Green B and examining after adding a 

 coverslip. Mitochondria become col- 

 ored a dark bluish-green after 5-10 min. 

 They first appear in the lymphocytes 

 and then between the granules of the 

 granular cells. R. R. Bensley (Am. J. 

 Anat., 1911, 12, 297-388) has described 

 a method of intravascular staining of 

 mitochondria using Janus Green B. 

 Janus Green preparations of mito- 

 chondria are not permanent — they 



