658 LECTURE XXVIII. 



upon artificial feeding, it will be hard for it to utilize the nutriment to best 

 advantage. The child has at the start a defective circulation. It is hard 

 for the weakened cells to carry out a thorough assimilation and trans- 

 formation of the food materials. They tend to become weaker and weaker, 

 and lose more and more the ability of reconstructing the material. Numer- 

 ous complications lessen the value of the artificial nourishment which the 

 child receives. If milk from an animal is used, large amounts of micro- 

 organisms are invariably present which cause unfavorable effects in the 

 bowels of the child. These organisms may be killed by sterilization, and 

 then their harmful effects will not be felt, but on the other hand it has been 

 found that in sterilization changes are produced in the milk itself which 

 make it more difficultly digestible. Perhaps it serves to "denaturize" 

 the proteins in the milk, so that it is harder for the ferments to act upon 

 them. It has been found possible to carry out the sterilization process 

 in such a way that this injury to the milk itself is reduced to a minimum. 

 One great danger to be feared in the artificial feeding of infants is the over- 

 loading of the alimentary canal. Under normal conditions the infant has 

 to work pretty hard to get its food. In sucking out the milk the child 

 becomes tired, so that after a time it stops feeding. 



Social relations undoubtedly exert a great influence upon the prevailing 

 conditions. Many people resort to artificial feeding because they believe 

 the conditions are unfavorable, and even when the mother's milk is given, 

 it is so seldom in accordance with natural conditions, that even these 

 infants do not develop normally. It should be our task to educate people 

 to believe that mother's milk is the proper food for the child, and that it 

 alone affords a positive guarantee for the normal development of the 

 infant. At the same time it should also be our aim to carry out researches 

 in the hope of discovering more satisfactory substitutes for the mother's 

 milk when it is not available. As we have said before, the nourishment 

 of the child should in no case be regulated solely with regard to the fuel 

 value of the food. The most important thing is to make sure that it will 

 serve for the construction of tissue. A milk substitute may be absolutely 

 worthless in spite of the fact that it has a high calorific value. Especially 

 at this time of rapid development the Law of the Minimum holds in its 

 entirety. By no means should the nature of the organic constituents 

 alone come into consideration. It is equally important that the inorganic 

 requirements should be satisfied. Furthermore, it is not even sufficient 

 to know the total amount of the inorganic material. 



In the case of mammals the milk nourishment continues only during 

 the lactation period, and is then abandoned entirely within a relatively 

 short time. We have already seen in studying the iron content * that 



1 Cf. Lecture XVII, p. 386. 



