370 



LECTURE XVI. 



It is evident from these values that most of the foods are deficient in lime 

 alone, as compared with milk. Now while we are not justified in assuming 

 that the lime-content of milk is to be considered as the normal amount 

 required for man's later development, still, on the other hand, we must 

 not forget that probably the " law of the minimum " holds for animal 

 organisms as well as for plants. Now lime plays a quite particular part 

 in the development of the organism, especially for certain tissues, the 

 bones and teeth. It is clear, therefore, that the system must have an 

 adequate supply of the lime at its disposal. Of course the fully developed 

 organism requires lime as well, for even then, as we have already seen, 

 there is a constant building up and wearing down of tissue, and especially 

 of bony tissue. The following table gives the amount of lime present in 

 many of our foods. At the same time the amounts of iron they contain 

 are also given. The values refer to 100 grams of substance dried at 120 C. 

 They are arranged with increasing lime-content. 



These values show that it is by no means immaterial what food the 

 infant receives at the time it leaves the mother's breast. When the child 

 is six months old, it takes about one liter of milk daily. This amount 

 contains, in round numbers, about 0.5 gram of lime. We do not know 

 exactly how much lime the nursing infant requires at the time it is 

 weaned. We can safely assume, however, that in the later periods of its 

 growth, it requires relatively less. For one thing, the development takes 

 place more gradually than is the case shortly after birth; and, again, the 

 absolute amount of lime taken into the system increases with the quantity 

 of food eaten. The following figures will give some idea of the rapidity of 

 the development shortly after birth. Rabbits double their weight at the 



