Pigmented Kevatinous Materials 



303 



Mr. Skertchly. They found that all equatorial x-ray 

 reflections, obtained from Lincoln wool, appear, 

 within narrow limits, to be either orders of, or related 

 to, the reflections near 250 A. They traced many 

 orders up to the 57th and regard this as an indica- 

 tion of a considerable degree of unidirectional order, 

 consistent with a sheet-like structure. The same 

 workers have also suggested the possibility of the 

 existence of a hexagonal close-packing of the 

 microfibrils. This point, however, can be resolved 

 only by the direct examination of cross-sections of 

 fully hardened keratin fibres. 



We wish to thank Messrs. H. J. Woods and A. B. 

 Skertchly for placing at our disposal their unpublished 

 results. One of us (M. W. A.) is indebted to the C.S.I. R.O. 

 (Australia) for an overseas studentship which enabled 

 this work to be carried out. 



References 



1. ASTBURY, W. 



(1953). 



T., Proc. Roy. Soc. (London) B 141, 1 



2. — Inlcni. Wool Text. Res. Conf., Australia, 1955 (in 



press). 



3. Burgess, R., J. Textile Inst. 25. T 391 (1934). 



4. Fraser, R. D. B., Intern. Wool Text. Res. Conf., Austra- 



lia, 1955; during discussion (in press). 



5. Jeffrey, G. M. and Sikorski, J., Ann. Conf. of the Elect. 



Microsc. Group of the Inst, of Phys., 1956. Brit. J. 

 Appl. PItys. (summary in press). 



6. Jeffrey, G. M., Sikorski, J., and Woods, 11. ,1 , liuern. 



Woo! Test. Res. Conf., Australia, 1955 (in press). 



7. — Te.\tile Research J. 25, 714 (1955). 



8. KoNDO, T. and Horio, M., Textile Research J. 23. 373 



(1953). 



9. McArthur, I., Proc. Roy. Soc. (London) B 141, 33 



(1953). 

 10. MiRCF.R, li. H., Textile Research J. 23, 380 (1953). 

 1 1. Pauling, L. and Corey, R. H., Nali4re 171, 59 (1953). 



12. RoGi RS, G. E., Conf. on Hiectr. Microsc. of Text, and 



other Industrial Fibres, Inst, of Phys., Leeds. 1956; 

 summary by Challice, C. E. and Sikorski, J., Brit. 

 J. Appl. Phy.f. (in press). 



13. Sailow. G. and Sikorski, J., Melliand Textilher. (in 



press). 



14. Sikorski, J. and Woods, H. J., Conf. on Electr. Microsc. 



of Text, and other Industrial Fibres, Inst, of Phys., 

 Leeds, 1956; summary by Challice, C. E. and 

 Sikorski, J., Brit. J. Appl. Phys. (in press). 



15. Woods, H. J., Proc. Roy. Soc. {London) A 166, 76 (1938). 



The Electron Microscopy of Pigmented Keratinoiis Materials 

 J. Hope, J. Sikorski, and C. S. Whewell 



Textile Chemistry^ and Textile Physics'- Laboratories, 

 Department of Textile Industries, University of Leeds 



The study of colouring matters found in keratinous 

 materials has an important bearing on many prob- 

 lems encountered in biology, genetics, medicine 

 and industry. During recent years it has been possible 

 to make accurate determination, for the first time, 

 of the size and shape of the pigment-containing 

 granules (4, 8, 11). In more recent studies valuable 

 information has been obtained on the size and shape 

 (1,6 and Bohren and Buss, private communication) 

 and the disposition (1,2, 6, 9) of pigment-containing 

 granules in the keratin matrix. 



The examination of ultra-thin sections of pig- 

 mented follicles (1, 2, 9) and cf isolated melanin 

 granules (2) has revealed that the latter are aggre- 

 gates of dense particles. In some granules the mela- 

 nin could be considered as deposited in parallel 

 lamellae (1, 2, 9 and Charles, private communica- 

 tion) which may form a succession of cylindrical or 

 ellipsoidal shells. 



One of the main problems in investigating keratin 

 pigment is to devise a method for isolating pigment- 



1 J. Hope and C. S. Whewell. 



- J. Sikorski. 



3 Three hours were required to isolate the pigment-contain- 

 ing granules, by centrifuging the PHT suspension (10 ml) 

 at 10,000 g (instead of 10 hours at 2000 g, in 50 ml tubes; 

 Laxer et al. (6)). 



containing granules free from contamination by residual 



keratin without ad\erse moditication of their morphologi- 

 cal and crystal structure (6). The following methods have 

 been used for isolating pigment-containing granules from 

 feathers and mammalian hairs: (i) enzymatic digestion 

 (2); (ii) treatment in urea solutions, containing papain 

 and sodium metabisulphile (2); (iii) boiling in Nji 

 potassium hydroxide (I, 2); (iv) boiling or relluxing in 

 3 A' (2), 6 A (6, I and Bohren and Buss, private commu- 

 nication) or concentrated h\drochloric acid (II); (v) 

 refluxing in an iron-free solution containing 94 g of 

 phenol, 9.0 g of distilled water and 8.2 ml of thioglycollic 

 acid-PHT reagent (6). 



It is evident that granules isolated by most of the 

 above methods are modified to some extent, if the 

 method is modified so that the isolated granules 

 appear to be intact, there is generally a great degree 

 of contamination by residual keratin. This empha- 

 sized thedesirability of electron microscopic examina- 

 tion as control technique for indicating the efficacy 

 of any process for separating granules from kerati- 

 nous materials (6). The PHT (phenol hydrate and 

 thioglycollic acid) method, however, was found to 

 satisfy both criteria discussed above, but it does 

 involve certain experimental difticullies of separating 

 out the granules from viscous solutions.' 



An examination of various methods of isolating 

 pigment-containing granules in keratinous materials. 

 All the methods examined of isolating pigment- 



