NUTRITION AND GROWTH: I. 



29 



by the following data, taken from those recorded for the two dogs of 

 experiment IV, one of which (D) was killed seventy- five days before 

 the other (C). While the live weight had increased from about 2,000 to 

 3,400 grams, the weights of the brains at the two different periods are 

 52 and 60 grams, respectively; i. e., there was 70 per cent increase in the 

 live weight, and only 15 per cent increase in brain weight. 



According to data taken from Monti ^^ the brain of a child increases 

 in weight from three to four times, while the weights of other organs 

 increase about ten times. 



The skin shows a slightly higher percentage of the body weight in 

 those animals kept at a constant weight than in the normal, control dogs. 



Experiment I . 



Dog. 



Experiment II . 



II (C)»_ 



III (C). 



IV (N)» 



(V (N) . 

 IV'l (C) . 



Experiment III . 



(XI (O — 

 IviII (N). 



Weight of skin 

 in per cent of 

 body weight. 



Fresh. Dry 



13.6 

 14.6 

 12.0 



11.2 

 12.5 



12.2 

 13.0 



5.35 

 5.09 

 4.21 



* (N) Grew under normal conditions. (C) Kept at a constant weight. 



These figures indicate that, while the weight was constant, the skin 

 increased very slightly in, weight. 



Only the flesh, muscles, and fat of the body remain as the tissues 

 which must have lost during the course of the experiments. The degree 

 of this loss of flesh will be best recognized by considering the chemical 

 composition of the different animals. 



CHANGES IN THE CHEMICAL CONSTITUTION OF THE BODY. 



The quantities of the different constituents are reduced to percentages 

 of the live or body weight in order to facilitate this calculation. The 

 absolute quantity of protein, fat, etc., is, of course, smaller in the dogs 

 kept on a low diet than in the normally fed animals. This may not 

 be absolutely correct in regard to the fat if the control animal was 

 overfed during the course of the experiment. However, if the quantity 

 of fat is far below the values which we find in the normal animals, there 



" Das Waehstum des Kindes in "Kinderheilkunde in Einzeldarstellungen" 

 (1898), 555. 



