1146 GROWTH. [BOOK iv. 



or three years, then remains nearly stationary or even rises, and 

 at about the seventh or eighth year undergoes a marked fall. 

 This fall, however, is temporary only; the curve soon rises 

 again and with some irregularities attains a maximum between 

 the twelfth and fifteenth year, from which point onwards it falls 

 rapidly with some minor irregularities. These marked varia- 

 tions in the increment of growth which are obviously connected 

 with and preparatory to the important change which we call 

 puberty, are seen in the curves both of stature and of weight, 

 the changes in weight occurring however rather later than those 

 of stature, and both being somewhat different in boys from what 

 they are in girls. Both are also influenced by the conditions of 

 life; but a study of the curves of growth of young people living 

 under various surroundings, while it teaches the great impor- 

 tance of properly administering to the wants of youth, at the 

 same time illustrates the recuperative elasticity of the bodily 

 frame; it may often be observed that the ill effects of adverse 

 circumstances, provided they be not too great, are soon recov- 

 ered from under the influence of a happy change ; food and 

 comfort will turn the abnormal fall in the curve of growth of a 

 starved waif into a sharp rise. 



Lastly, we may study growth by observing the actual rate of 

 growth, by measuring the magnitude of the fraction of the total 

 weight which is added to the weight in a given time ; we take 

 weight because this is the most significant element of growth. 

 When this method is adopted, an examination of such statistics 

 as are available with regard to man, confirmed by the results of 

 careful observations on young animals, tends to shew that the 

 rate diminishes continually from birth onwards, the diminution 

 being rapid at first but slower afterwards, and being broken by 

 various irregularities. In other words, the power of growth 

 diminishes continually though somewhat irregularly throughout 

 life, and a like diminution apparently obtains in intra-uterine 

 existence. It seems as if the impetus of growth given at im- 

 pregnation gradually dies out. 



714. The saliva of the babe, very scanty at first and not 

 abundant until teething begins, is active on starch though less 

 so than in the adult, and its gastric juice, unlike that of many 

 new-born animals, has good peptic powers, and its pancreas 

 good tryptic powers, though apparently the pancreatic action 

 on starch is feeble. From this we may infer that its digestive 

 processes are in general identical with that of the adult though 

 ill suited for any large amount of starch in the food ; and they 

 are feeble, since the faeces of the infant contain a considerable 

 quantity of undigested food (fat, casein, &c.), as well as un- 

 altered bile-pigment, and undecomposed bile-salts. 



The heart of the babe, as shewn in the preceding Table, is, 

 relatively to its body-weight, larger than the adult, and the 



