CHAPTER II. 



INCREASE IN THE WEIGHT OF THE ENTIRE BODY. 



Terms Divisions of the life cycle Growth and development 

 Growth of the entire body Variations in the specific gravity 

 of the different systems Proportion of water Weight the 

 best measure of growth Change in the proportions of the 

 body with age Data on weight Corrections for clothing 

 Descriptions of curves Absolute increase in weight Com- 

 position of statistics General and individual methods Effects 

 of illness Influence of environment Influence of size at- 

 tained on subsequent growth Weight and stature of first-born 

 Growth before birth Determination of weight at birth In- 

 crease during the first year Rate of growth Unit of energy. 



UNDER the term growth are included several sets of 

 changes which should be distinguished. In following 

 a mammal from birth to the completion of its individual 

 existence, a constant series of alterations in its physical 

 characters is to be noted. From infancy to maturity 

 the animal increases in all diameters and in weight. 

 To these physical changes the term growth has com- 

 monly been limited. But after reaching maturity there is 

 a period when the changes become very slow, and this is 

 later followed by the involutionary processes of old age. 

 The second and third acts are as important a part of the 

 life cycle as the first, and yet in the last the physical 

 changes are predominantly those of decrease. The 

 possibilities of confusion do not, however, end here. 



Both the size and weight of the animal may vary by 

 alterations in the amount of fat, and yet such variations 

 do not, strictly speaking, belong to the phenomena of 



