WEIGHT INCREASE AND INCREASE IN STATURE. 71 



The figures for the males show the liver to be ultimately 

 the heaviest organ, and the brain next in weight, 

 although at birth the brain is by far the bulkiest of the 

 entire group. It is found, however, that its relative 

 growth is less, and very much less, than that of the 

 other organs, and as one consequence the percentage 

 decrease in the weight value of the brain is the greatest. 

 The growth of the brain is most rapid during the first 

 year. It will not escape notice that the maximum 

 weight reached by the brain occurs in the table (in heavy 

 type) for the males at fifteen years, and in that for the 

 females, at ten years. This peculiarity will be discussed 

 later on, and here it only need be remarked that there is 

 no evidence for the view that in a given individual the 

 brain at this period is heavier than it is during the next 

 two decades. The most rapid weight increase of the 

 other organs centres about the time of puberty, and 

 tends to precede the maximum weight increase for the 

 entire body ; suggesting, therefore, that the muscular 

 system is the last to respond. The relative growth of 

 the left lung approaches most nearly that of the body as 

 a whole, while the liver shows the greatest acceleration 

 at puberty. Thus far, what has been said of the males 

 applies to the females also. 



There are a number of points, however, in which they 

 differ. In the female at birth the brain, heart, right 

 lung, and spleen are recorded as heavier than in the 

 male, although the total body-weight is less. Both the 

 relative and absolute increase in the male is greater for 

 every organ except the spleen, while the percentage of 

 the total body- weight as represented by those organs at 

 maturity is less in all instances. The increase in the 

 liver at puberty is most marked in the female. If we 

 bring these facts together, it appears that the brain 

 grows in a manner different from the viscera of the 



