HAIRS 



152 



HARRIS ALUM HEMATOXYLIN 



and repeatedly in ether-alcohol, or the 

 shaft and root can be cleared and 

 mounted in balsam for repeated study. 

 In case it is too highly pigmented to 



Eermit a clear view of its structure first 

 leach with hydrogen peroxide. Indi- 

 vidual cells of the shaft can be isolated 

 by maceration in 40% aq. potassium 

 hydrate. 



Scale counts are made readily after 

 a dry mount has had applied a drop or 

 two of a glycerine-alcohol mixture at 

 the ends of the specimen. This mix- 

 ture progresses along the shaft by 

 capillary attraction thus bringing into 

 relief the free borders of the scales 

 (Trotter, M. and Duggins, O. H., Am. 

 J. Phys. Anthrop., in press). Deter- 

 mination of the cuticular scale pattern 

 may be made after partially embedding 

 the hair in a glycerine jelly (Eddy, M. 

 W. and Raring, J. C, Proc. Acad. Sci., 

 1941, 15, 164-168). Study of the cortex 

 (fusi and pigment granules under very 

 high power) and medulla (when present 

 with its clumps of pigment) requires 

 clearing by immersing in some oil the 

 refractive index of which is approxi- 

 mately the same as that of the hair 

 (Hausman, L. A., Sci. Month., 1944, 

 59, 195-202). 



The refractive index of hair may be 

 determined to the greatest accuracy by 

 the double-variation method using both 

 the Becke line and half shadow tech- 

 niques (Gibb. T. R. P., Jr., Optical 

 Methods of Chemical Analysis, pp. 

 249-250, McGraw-Hill, 1942). Cut 

 hairs into a number of 1 mm. lengths, 

 agitate for 30 minutes in ether-alcohol 

 and mount in oil of a similar refractive 

 index on a temperature cell under a 

 polarizing microscope. True index is 

 found only at crossed Nicols. It is 

 suggested that the index be taken both 

 perpendicular to the lower Nicol (90°) 

 and parallel to the lower Nicol (0°) 

 and that the lower index (90°) be sub- 

 tracted from the higher index (0°) in 

 order to determine the birefringence. 

 The Becke line method may be followed 

 by the half shadow method for greater 

 accuracy. The limit of accuracy will 

 be approximately +3 in the third place. 

 In addition, it is suggested that the use 

 of the phase microscope for such deter- 

 minations may increase the accuracy to 

 the fourth decimal place. 



Cross sections of a large number of 

 hairs (appro.ximately 150) may be made 

 at one time with very little preliminary 

 preparations by using the "Dr. J. I. 

 Hardy Thin Cross-Section Device" 

 (Gosnell Mfg. Co., Washington, D. C). 



The root and the follicle are to be 

 seen in most sections of hairy skin and 



require no special technique unless one 

 wishes to study the follicles attached to 

 whole mounts of epidermis. In order 

 to study the growth of a given hair or 

 to determine the cyclic activity of its 

 follicle it is convenient to place a small 

 tattoo mark with India ink in the skin 

 near the mouth of the follicle (Trotter, 

 M., Am. J. Phys. Anthrop., 1924, 7, 

 427-437). 



Distribution of alkaline phosphatase 

 in growth of hair follicle (Johnson, 

 P. L., Butcher, E. O. and Bevelander, 

 G., Anat. Rec, 1945, 93, 355-361). For 

 further details see Trotter, M., Chapter 

 on Hair in Cowdry's Special Cytology, 

 1932, 1, 40-65. Cleaning and mounting 

 of individual hairs (Duncan, F. W., 

 J. Roy. Micr. Soc, 1943, 63, 85-88. 

 Microphotography of keratin fibers of 

 hairs (Stoves, J. L., J. Roy. Micr. Soc, 

 1943, 63, 89-90). The less pigment in 

 the hair, the greater the fluorescence, so 

 that gray hair is clear white. Hair 

 containing tricophyton or microsporon 

 fluoresces bright green. See Kinnear, 

 J., Brit. Med., J., 1931, 1, 791-793 on 

 diagnosis of ringworm. 



Halides, microscopic localization in tissues 

 by precipitation methods (Gersh, I. 

 and Stieglitz, E. J., Anat. Rec, 1933, 

 56, 185). 



Hal ©meter, apparatus designed by Eve, 

 F. C, Lancet, 1928, 1, 1070 to measure 

 mean diameter of erythrocytes, see 

 Erythrocytometer. 



Halowax, see Paraffin Sections. 



Hanging Drop preparations are mostly em- 

 ployed in the examination of living 

 bacteria and protozoa. A drop of the 

 fluid is simply attached to the under 

 surface of a cover glass which is mounted 

 over a depression in a slide. Equally 

 satisfactory results can usually be 

 obtained by simply mounting under a 

 cover glass on an ordinary slide unless 

 the greater depth of the hanging drop is 

 required. When in Microdissection it 

 is necessary to get at the cells from the 

 under surface of the cover glass special 

 chambers and hanging drops are em- 

 ployed. 



Harderian Glands, fluorescence in mice 

 (Strong, L. C. and Figge, F. H. J., 

 Science, 1941, 93, 331). Technique for 

 rat is given by Grafflin, A. L., Am. J. 

 Anat., 1942, 71, 43-64. 



Harleco Synthetic Resin is recommended 

 by McClung, Microscopical Technique, 

 1950, p. 24 as a mounting medium some- 

 what similar to Clarite. It can be ob- 

 tained from Hartman-Liddon Co., 5821 

 Market Street, Philadelphia 39, Pa. 



Harris Alum Hematoxylin. Dissolve 1 gm. 

 hematoxylin in 10 cc absolute alcohol 

 and 20 gms. ammonium or jrotassium 



