INORGANIC FOODS. 375 



that more lime is received in the later years, for, as a matter of fact, milk, 

 which is invariably the basis of infant diet, contains more lime than almost 

 any other article of food, so that the infant receives relatively more lime 

 than at any subsequent time. 



It is to be expected that the formation of the bones will be seriously 

 affected if the lime in the food is intentionally made inadequate. Thus 

 when Forster l and likewise Voit 2 fed young dogs with meat, fat, and 

 water, free from calcium, a faulty bone-formation was soon apparent. 

 Chossat, 3 and later on Voit, 4 observed that fully developed pigeons, which 

 were made to subsist for a year exclusively upon washed wheat grains 

 and distilled water, showed a deficient skeleton. The bones were very 

 fragile, the skull and breast-bone- being very thin, and penetrated with 

 sieve-like perforations. These experiments merely prove that the bones 

 require lime for their development. Such experiments have no connection 

 at all with the disease of rickets. Particularly, the observations made 

 with the pigeons remind one very much of osteoporosis, a morbid absorp- 

 tion of bone which often takes place in elderly people, especially in the 

 region of the skull, and is obviously due to inadequate nourishment of the 

 bony tissue. 



Up to this point we have only traced the metabolism of the animal 

 organism in two periods, namely, during growth and after the organism 

 is fully developed. An especial observation with regard to the content 

 of the food in inorganic salts is furnished by the organism of the mother 

 during pregnancy and during lactation. At this time the organism of 

 the child develops exclusively at the expense of the mother. If the material 

 received by the mother in the food during this period is not sufficient, 

 then the stores of her organism are attacked, and finally her own tissue 

 is subject to resorption. The foetus develops continually even when the 

 mother is starving. Remarkable migrations of substance must take 

 place during this entire process. Our knowledge concerning these rela- 

 tions is still very incomplete. The following table prepared by Hugon- 

 nenq 5 gives an idea of the amount of inorganic material taken up by the 

 foetus during its development. 



We see from these values that towards the end of pregnancy there is 

 suddenly a marked increase in the amount of inorganic material taken up 

 by the foetus. During the last three months it takes up almost twice as 

 much inorganic material as during the first six months of its development. 

 Altogether it withdraws about 100 grams of ash constituents from the 



1 Z. Biol. 9, 369 (1873); 12, 464 (1876). 



2 Urid. 16, 85 (1880). 



3 Compt. rend. 14, 451 (1842). 



4 Ber. Vers. Deut. Naturforscher, Miinchen, 1877, 243. 

 6 Compt. rend. 128, 1054 (1899), 



