SCIEXTIFIC STUDY OF THE CHILD. 765 



Sometimes the bones grow and the muscles remain gtationaiy, and 

 vice versa; then the child has growing pains. The legs grow faster 

 than the trunk. Up to the twelfth year in girls and the fifteenth 

 year in boys, a large part of the growth in size occurs in the legs, but 

 after these ages in the trunk. In the leg tlie thigh often has the 

 greatest growth ; the lower part reaches its limit at about sixteen 

 years, while the thigh continues to grow for at least three years 

 longer. The forearm grows most slowly when height is increasing 

 most rapidly. The growth of the child is not a steady, harmonious 

 development, but it is a case of " here a little, and there a little." 



The growing energy of one part is exhausted, and that part 

 ceases to grow until it gathers a fresh impetus and forges ahead once 

 more. There is a diminished rate of growth in both height and 

 weight for about six years before puberty, beginning at the period of 

 second dentition. Just before puberty, however, there is a great 

 outburst of growth energy, which in girls precedes that in boys by 

 about two years. Girls from thirteen to fifteen years of age ar© 

 taller than boys of the same age, according to some American 

 measurements, and at one stage girls are heavier than boys of th© 

 same age. The thorax becomes relatively broad and flat as the child 

 advances from infancy to puberty, and at the latter age its circum- 

 ference increases most rapidly. The circulatory system at puberty 

 becomes more expressive — blushing, losing colour, change in rate of 

 heart heat. All now occur in response to mental states. Length of 

 face is the head dimension, which increases most rapidly at th© same 

 age, and there is a gradual increase in breadtli of skull in boys from 

 the age of fourteen to eighteen, and from twelve to fifteen in girls. 

 Th© vascular system is exceedingly variable in its growth, and great 

 changes take place at this time. Before the time of puberty the blood- 

 vessels are large, and the heart small. After that time the heart is 

 large and the vessels small. This enlargement of the heart is so great 

 that it would lessen to a considerable extent the vital capacity wer© 

 the reduction not compensated by the increase in lung power. Th© 

 infant breathes at the rate of about forty respirations per minute; 

 by the age of fifteen that rate has slowed down to about half that 

 number. This is a meagre outline of some interesting features of 

 the phenomena of growth — the explanation of many of which is still 

 tj seek. 



Before we proceed further, it is necessary to refer to a theory 

 which is regarded as fundamental by the votaries of the new science of 

 child-study. This is the recapitulation theory of the evolutionist. 

 The individual more or less repeats in his development, physical and 

 mental, the chief stages in the development of the race. " Ontogeny 

 is a recapitulation of phylogeny." This principle of recapitulation 

 has been more prominently recognised in connection with the science 

 of embryology. And, indeed, the argument from embryology was on© 

 of the most convincing proofs of the " descent of man." But th© 

 principle is now being extended further, in so far as it is held to 

 apply to the development of the individual up to maturity. Th© 

 individual is not fully grown tiU he he has reached the maturity of 

 th© adult. As there is a natural development before birth, 

 so there is a natural development after birth, and the 



