35 PHYSIOLOGICAL CHEMISTRY. 



The sulphur in hair is in part loosely combined and may 

 be split off easily by reagents, alkalies for example. The ash 

 of hair is rich in sulphates and contains also silica and other 

 mineral substances. Much of the ash may be removed by 

 washing the hair with weak acids, following treatment with 

 ether and alcohol to remove fatty and other soluble substances. 

 The purified " keratin " thus secured gives results like the 

 above on analysis. 



Horn and nails contain along with the insoluble keratin 

 insoluble salts, mainly phosphate of calcium, which stiffen 

 them. From very fine horn shavings these salts may be dis- 

 solved out by acids, leaving a soft flexible keratin. 



