838 THE SKIN AND ITS SECRETIONS. 



The quantity of sulphur and of mineral bodies is of certain interest. 

 The sulphur and cystine content of these structures can be found on 

 pages 113, 114 and in this connection it must be mentioned that, accord- 

 ing to the investigations of RUTHERFORD and HAWK/ the sulphur content 

 of human hair is higher in men than in women, at least for the Caucasian 

 race, and ajso that red hair has the highest sulphur content irrespective 

 of race or gender. Hair on incineration leaves considerable ash, which 

 in human hair varies between 2.6 and 16 p. m., and in animal hair 

 is still greater, even up to 71 p. m. in the hair of the deer. The ash 

 consists of large amounts of alkali and calcium sulphate, and its sulphur 

 probably originates from the organic substance, which make the state- 

 ments as to the composition of the ash of hair of little value. Calcium 

 occurs in larger amounts, especially phosphate as well as carbonate, and is 

 most abundant in white hair. The amount of iron oxide in 1000 grams 

 of the ash of human hair varies between 42.2 grams in blond and 108.7 

 grams in brown hair, and silicic acid between 66.1 grams in black and 

 424.6 grams in red hair (BAUDRIMONT). The nails are rich in calcium 

 phosphate, and the feathers rich in silicic acid, especially the feathers 

 of grain-eating birds. According to v. GORUP-BESANEZ 2 the quantity 

 of silicic acid in grain-eating birds was 400 p. m., and in meat, berries 

 and insect-eating birds the amount was only 270 p. m. of the total ash. 

 DRECHSEL claims that at least a part of the silicic acid exists in the 

 feathers in organic combination as an ester while according to CERNY 3 it 

 exists only as an accidental contamination. 



According to GATJTIER and BERTRAND 4 arsenic also occurs in the 

 epidermal formations. GAUTIER says that arsenic is of importance in 

 the formation and growth of the formations, and on the other hand the 

 hair, nails, and epidermis-cells are of great importance in the excretion 

 of arsenic. 



The ability of the skin to take up chlorides as observed by WAHLGREN 

 and by PADTBERG, 5 is remarkable. According to them the skin is an 

 important chloride depot, which stores up chlorides when supplied in 

 excess and gives them up when necessary. 



The skin of invertebrates has been the subject, in a few cases, of 

 chemical investigation, and in these animals various substances have 

 been found, of which a few, though little studied, are worth discussing. 

 Among them tunicin, which is found especially in the mantle of the 



1 Journ. of Biol. Chem., 3. 



2 Lehr. d. physiol. Chem., 4. Aufl., 660, 661; Baudrimont, ibid. 



3 Drechsel, Centralbl. f. Physiol., 11, 361; Cerny, Zeitschr. f. physiol. Chem., 62. 



4 Gautier, Compt. Rend., 129, 130, 131; Bertrand, ibid., 134. 



5 Wahlgren, Arch. f. exp. Path. u. Pharm., 61; Padtberg, ibid., 63. 



