STRUCTURE AND SYNCHRONIZED STRETCH-ROTATION OF HAIRKERATIN 33 that the process is continuous from the beginning to the breaking point, and is not replaced at the limit of proportionality by a different process but is superimposed upon it. The first part of the process is not therefore con- nected, or only slightly so, with cystine length. It could easily be due to the primary polypeptide spir, 1. The second part of the process super- imposed upon it always occurs as part of the load-stretch curve. It only occurs in the load-rotation curve if the hair is untreated. It would appear as if the component loses its spiral character when the crosslinks are removed, or as if an element could be simply pulled out, instead of having to be screwed out with a rotational movement, after the links have been broken. Many a mystery could be explained if during this process the /•-screws of the AB6 strands •0 which turn in the opposite direction to the central, automatically twisting A screws, took part in this. The element which starts moving from the hmit of proportionality seems to be connected by cystine bridges with the element which is untwisted from the beginning of the process. The results obtained with human hair cannot be assumed to automatically extend to animal hair. Experiments with the latter, hke studies with other high polymers appear promising, iudging by the work o[ Gold- worthy and Lang •2. These authors measured the velocity of the rotation of wool fibres in both directions, weighted with 6 mg in various fluids, and explained the rotation in terms of the relaxation o[ pre-existing tensions. EXPERIMENTAL DATA To explain symbols not yet elucidated in Figs. 1-3 and Formulae 1-3 ß l, -- 10 A = % length of the initial stretch -- lo . 100 {%) (4) M = % length of the middle stretch -- ß 100 (%) (5) T = % length of breaking stretch -- . 100 (%) (not final stretch) lo At, Mr and Tr are the rotational values in degrees, taken from: the initial stretch = n, the middle stretch = n2 -- n• the breaking stretch -- ns Pr are the P values of rotation. (6) As each exper ment consisted o' several measurements, only the average of each experiment is quoted. All experiments at constant humidity.

34 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS •Experiment 1 Blank with untreated hair EH34. 2 Hair EI-I34 after boiling in water for 10 minutes. 3 Hair EH34 after treatment with 5 per cent sodium bisulphite at 67 ø C for 5 minutes. 4 Hair EH34 after treatment with 5 per cent sodium bisulphite at 97 ø C for 5 minutes. 5 Hair EH34 which was thrown into 5 per cent sodium bisulphite solution at 65 ø C. The latter was brought to the boil by steadily raising the temperature for 10 minutes. a. Coarse hair, and b. Thinner hair. 6 Blank with untreated hair EF18. 7 Hair EF18 after I- hour's treatment with conc. ammonia. 8 Hair EF18 after I- hour's treatment with ammoniacal thio- glycollate, rinsing subsequently. The strength of the solution was 10.06 per cent in respect of thioglycollic acid--pH: 9.5 (Merck special indicator). TABLE 1 Expt. No. Hi ttir Qttir A M T Ar Mr Tr P• P2 Pa Pr• P% Pr a 1 1.7 4.9 2.9 12.3 20.5 54 59.5 30 110.5 50 62.5 87.5 47.5 60 87.5 2 3.4 3.5 1-0 12 18 58 52 12 I 82 45 55 75 45 50 75 3 ' 1-8 3.2 1.8 11 22 61 57 13 99 50 60 95 50 55 95 __ 4 •o o• 1 12 52 -- -- 40 40 5a* 8.4 o• o• 4 20 32 49 20 30 60 60 5•--I o• o• 1 (9)+ -- 13 50 (30)+ • 35 35 -I 6 10.9 7.4 0.68 8 17 60 22 9.4 46 20 25 55 20 25 55 7 11.1, 7.0 0.63 20 21 72 23 9.5 52 20 25 55 20 25 55 8 34.8 H o• 10 90 190 -- -- 31 15 20 25 25 I * Only determination of all values. t Only determination of this value. To show the number of measurements which were taken to arrive at the above results, the data of a single experiment are given in Table 2, and the results derived therefrom in Table 3. TABLE 3 Hi Hit QHir A M T Ar Mr Tr P• P• Ps Pr• Pr• Pra 3.5 14.9 4.3 6 20 44 151 140 401 35 51 75 35 50 75