INORGANIC FOODS. 407 



ably due to differences in the material examined. The amount of arsenic 

 in animal tissues must depend upon the nature of the food. Gautier l 

 and Bertrand 2 have found arsenic, while others, as, for example, Kunkel, 3 

 have not. 



It should be mentioned finally that recently the claim has been made 

 that lithium is also a normal constituent of the human organism. Erich 

 Herrmann 4 found this element present in stages of development where 

 the nourishment had been provided solely from the blood of the mother. 

 The lungs were found to be particularly rich in lithium. \ , 



From what has been said, it is apparent that inorganic salts are of 

 great importance as foods, both for the developing and adult organisms. 

 The cells also require the presence of salts for the proper exercise of their 

 functions. The cells are constantly being broken down and built up anew. 

 The more recent investigations concerning the action of the separate salts 

 make it seem most probable that our knowledge concerning the part that 

 inorganic substances play in the metabolism of the cells will shortly be 

 widened greatly, and that before long the inorganic substances in our food 

 will be the subject of considerable more interest corresponding to their 

 importance. 



1 Compt. rend. 137, 295 (1903), and Bull. soc. chim. Paris, 29, 913 (1903). Cf. 

 also Compt. rend. 137, 158 and 232 (1903), and Bull. soc. chim. Paris, 29, 639 (1903). 



2 Ann. inst. Pasteur, 16, 553 (1902); 17, 1 (1903); Ann. chim. phys. 28, 242 (1903); 

 Bull. soc. chim. Paris, 29, 790 and 920 (1903), and Compt. rend. 137, 266 (1903). 



3 Z. physiol. Chem. 44, 511 (1905). 



4 Pflviger's Arch. 109, 26 (1905). 



