PATHOLOGY OF METABOLISM IN INFANCY 787 



other hand, found that doubling the amount of casein in the food of an 

 infant fed on breast milk resulted in a rapid gain in weight with good 

 retention of nitrogen, potassium, sodium, chlorin and water. They found, 

 however, a negative calcium balance. 



Against the view that an excess of protein in the diet is the only fac- 

 tor in producing the disturbance due to the overfeeding of milk is the 

 fact that infants suffering from this condition do very well when fed on 

 buttermilk enriched with carbohydrate, a mixture containing practically 

 the same amount of protein as whole cow's milk. More recently atten- 

 tion has been directed to the physico-chemical characters of milk and a 

 possible source of trouble when an excess of cow's milk is fed is seen in its 

 high "buffer" value, that is to say, the property of the milk which per- 

 mits it to unite with relatively large amounts of acid or alkali without 

 very much change in chemical reaction. Approximately three and one- 

 half times as much acid must be added to cow's milk in order to change 

 its reaction to a certain degree as is necessary to change the reaction of 

 breast milk to the same degree (Aron, Marriott(c)). Once cow's milk is 

 acidified more alkali is required to again render it neutral or alkaline in 

 reaction. This buffer action of milk is due largely to the inorganic con- 

 stituents of milk, principally calcium phosphate. Marriott (c) has pointed 

 out the fact that when cow's milk is fed to an infant previously accus- 

 tomed to breast milk the amount of hydrochloric acid secreted by the 

 stomach must be at least three times as great if the optimum degree of 

 gastric acidity is to be attained. If this degree of acidity were not at- 

 tained the passage of a less acid chyme into the duodenum would supply 

 lessened stimulus to secretin formation. In addition a larger amount of 

 alkaline intestinal secretions would be necessary to alkalinize the chyle 

 to the optimum degree as the presence of buffer substances tends to pre- 

 vent change of reaction to the alkaline side as well. We consider the di- 

 gestive glands of the infant as having sufficient capacity to care for the 

 amounts of breast milk necessary for the nutrition of the infant, but one 

 could hardly expect the digestive system of every infant to be capable 

 of increasing its capacity to the extent required when cow's milk is fed. 

 If the increased secretion necessary were supplied by the gastric and 

 intestinal glands, the mineral metabolism of the whole body would of 

 necessity be altered as a result of the abstraction of these elements from 

 the blood. 



From what has been said, it is evident that various factors may be 

 involved in the case of artificially fed infants who, despite an adequate 

 intake of food, fail to gain in weight and show a characteristic train of 

 symptoms. There is no unanimity of opinion as to just which factors are 

 the more important and methods of treatment based on one or the other 

 theory of pathogenesis, although successful still fail to make clear the 

 causative factors. 



