MICROSOMES 



155 



MITOCHONDRIA 



teins and pho.spholipins in definite 

 proportions. 



Microtome Knife, sharpening. There is no 

 easy method. Care and long practice 

 are essential. (See Bensleys, p. 57.) 

 For the usual oil and water stones a 

 ground glass is now sometimes substi- 

 tuted (Uber, F. M., Stain Techn., 1936, 

 11,93-98). 



Micrurgical Technique (Gr. micros, small 

 + ergon, work) is referred to under the 

 heading of microdissection. 



Miliado Yellow G (CI, 622)— Stilbene Yel- 

 low — a direct dye of light fastness 3. 

 Similar to Sun Yellow but lighter in 

 color (Eniig, p. 46). 



Millv, bacteria in, a modification of Newman 

 technic (Broadhurst, J. and Paley, C, 

 J. Am. Vet. Med. Assoc, 1939, 94, 

 525-526). To prepare stain add 0.4 cc. 

 cone. H2SO4 to 54 cc. 95% alcohol. 

 Mix with 40 cc. technical tetrachlor- 

 ethane in flask and heat to 55 °C. but no 

 higher. Add about 1.0-1.2 gm. methy- 

 lene blue while mixture is still hot. 

 Shake vmtil d3'^e goes into solution. 

 Then add 8.0 cc. 1% basic fuchsin in 

 95% alcohol. Mix, cool, filter and put 

 up in glass stoppered bottle. Spread 

 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. 



Millimicron (myu) = 1 /1000th 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 v/ith tyrosin 

 in vitro an intense red color jdelding red 

 ppt. not clianging to yellow within 24 

 lars. They give the following directions. 

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

 nitric acid (sp. gr. 1.42) making 4G% 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. Ma.ximum 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). 



Mingazzini Phenomenon in intestinal villi 

 interpreted as an agonal or early post- 

 mortem change (by Macklin, C. C. and 

 M. T., J. Anat., 1926, Gl, 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 (G. mitos, thread + chondros, 

 grain). Granules, rods and filaments 

 existing in the cytoplasm of practically 

 all living cells of plants and animals. 

 They can be studied in living cells 

 unstained, after supravital staining and 

 in fixed tissues. 



In mammals the best place to observe 

 them unstained is in pieces of pancreas 

 cut so small that when mounted in a 

 little physiological salt solution they 

 are 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 zj^mogen granules. 

 The proximal poles are nearer the sur- 

 rounding blood vessels and compara- 

 tively free from zymogen granules. In 

 them careful search, with the aid of a 

 good oil immersion objective, will reveal 

 the mitochondria as delicate but slightly 

 refractile filaments oriented in general 

 with their length parallel to the length of 

 the acinous cell. Even when well flat- 

 tened such preparations are too thick for 

 satisfactory examination in the dark 

 field. When, however, a mount of fresh 

 blood is studied in dark field the mito- 

 chondria can be distinguished as bril- 

 liantly illuminated short rods and 

 granules in the lymphocytes in which 

 they are not obscured, as in the granular 

 leucocytes, by masses of specific gran- 

 ules. Beautiful illustrations of mito- 

 chondria seen in the d^irk field are 

 provided (Strange ways, T. S. P. and 

 Canti, R. G., Quart. J. Micr. Sci., 1927, 

 71,1.) 



The easiest way to demonstrate mito- 

 chondria supravitally stained is to place 

 on each of a scries of say 6 slides a small 

 drop of 1:10,000 janus green B (diethyl- 

 safraninazo dimethylanilin chloride) in 

 0.85% sodium chloride solution. The 

 dye should be added from a 1% stock 

 solution in distilled water because the 

 powder does not dissolve easily in salt 

 solution. Prick a finger and touch a 

 small amount of blood to each lot of 



