THE KERATINIZATION PROCESS 



253 



Fig. 105. Combination of wool with hydrochloric acid and with potas- 

 sium hydroxide as a function of pH and temperature in the absence of 

 added salt. (The dotted lines show the correction by Harris and 

 Rutherford for the reaction of alkali with cystine.) (Reproduced by 

 permission.) 



PH 



Fig. 106. The effect of pH on the reduction in work to stretch a fibre by 

 30% for normal (O) and deaminated hair ( X ). (Speakman, 1934.) Peters 

 and Woods, 1956. (Reproduced by permission.) 



