660 
drate or proteid alone to get an energy quotient of a dangerous height 
without producing a food which either from its state of concentration 
or by reason of its bulk would be manifestly impossible to feed to any 
infant. On the other hand, slight increases of 1 or 2 per cent in the 
fat content of a food may have the effect of raising its caloric value 
to a dangerous extent. 
The action of an excess of fat in causing nutritional disturbances 
in infants operates in two ways; first, by reason of its action on the 
alkaline bases of the body, and second, by its influence on gastric 
digestion. 
Action of excess of fat on alkaline bases of body . — According to 
Czerny and Keller, the deleterious influence of an excess of fat in the 
diet is usually operative by reason of the abstraction such excess 
entails on the alkaline bases of the organism for the purposes of its 
saponification in the intestinal tract. It is obvious that, owing to its 
high caloric efficiency and the greater difficulty of its oxidation as 
compared both with proteid and carbohydrate, the general capacity 
of the organism for the absorption of fat is strictly confined within 
narrow limits. TThereas an excess of proteids and carbohydrates is 
disposed of rather easily by the process of metabolism, with fats such 
is not the case. An excess of fatty food is not absorbed, but remains 
in the intestine and is there saponified. This is not due so much to 
efforts of the organism to get rid of the fat in this way as to the 
natural tendency of fat to undergo this action when exposed to the 
action of alkaline fluids such as the intestinal secretions. In this 
way an excessive abstraction of the alkaline bases of the body takes 
place, which are in turn supplied to the body, in milk at least, in 
quantities merely sufficient for a* normal diet. The income, then, of 
these bases becomes less than the outgo, and a pathological condition 
due to this diminution is thereby induced. Owing to the greater 
energy required in its digestion, the tendency of cow’s milk is to 
remain longer in the intestinal tract. This gives greater opportu- 
nity for any excess of fat present to rob the body of alkaline bases by 
virtue of its saponification. As a consequence of the general richness 
of cow’s milk in this country, such danger of excess of fat must 
always be present when the milk used as an article of infant food 
is not controlled in this respect. It would seem that a milk which 
contains 4 per cent of butter fat were somewhat too rich and that a 
fat content of 3 to 3.5 per cent would be nearer the mark to insure 
success in infant feeding. The experience of dairymen tells us that 
calves do best on this ; moreover, the production of rich milk in cows 
is not attended by a corresponding increase in the salts present, as 
rich milk is a result of careful breeding for that purpose by man, and 
is not a condition original to the milk of the cow. 
