NUTRITION AND GROWTH: I. 



39 



Several authors (Oppenheimer,™ Kubner, Graham-Lusk -^ and Wilson-) have 

 attempted to formulate mathematical laws concerning the relation of the caloric 

 intake to the increase in body weight. Rubner states that all young mammals, 

 with the exception of man, in their first days of life need the same number of 

 calories (4,808) to increase their body weight 1 kilo. This law would apply 

 to a time when the food supply of the animal is controlled by nature, and we 

 could understand a uaiversal law tmder such conditions. However, it has already 

 been shown that a number of Rubner's data are quite arbitrarily selected and 

 that others, equally reliable, lead to different results. 



Oppenheimer has observed that the growth in grams of normal, breast-fed 

 children of the same age may be nearly proportional to the quantity of milk 

 ingested. 



This question has also been studied by Graham-Lusk, who, from his own experi- 

 ments on suckling pigs performed in connection with Wilson, and from older 

 experiments on dogs done by Eost,^^ has shown that, "during the normal develop- 

 ment of the young of the same age and species, a definite percentage of the food 

 (expressed in the caloric value) is retained for growth irrespective of the size 

 of the individual." 



While it is difficult to give a satisfactory explanation for this law 

 from the standpoint of energetics, it seems to hold true in practice. For 

 instance, Bamberg,^* in a recent investigation on young pigs fed with the 

 same milk, has obtained results from which we might also find a con- 

 firmation of Graham-Lusk's law: 



Number of pig. 



First five weeks of experiment. 



Weight at 

 start. 



Increase 



Quantity 

 of milk. 



J 

 Q 



C - - . 



Qrams. 

 1,963 

 1,743 

 1,850 



Grams. 

 5,004 

 3,557 

 2,632 



Grams. 

 4,621 

 3,469 

 2,344 



1.08 

 1.02 

 1.12 



D. 



E 



In spite of the entirely different quantities of milk taken, there is a 

 very surprising agreement between the quotients yr which indicate the in- 

 crease in weight per imit of food (milk) . 



'"Ztschr. f. Biol. (1909), 42, 147. 



==' Science of Nutrition, Philadelphia & London, 2. ed. (1909), 247ff. 



^Am. Journ. Physiol. (1902), 8, 197, 212. 



-^ Arh. a. d. kais. Gsndhtsmie. (1901), 18, 206. 



'*Jahrl. f. Einderheilk. (1910), 71, 670. 



