December 13, 1912] 



SCIENCE 



815 



system whose harmomous operation de- 

 pends upon an agent which dominates all 

 the elements or all the substance within 

 the system. The lesser mechanism of the 

 autonomous element in the one hypothesis 

 and the greater control mechanism of the 

 other hypothesis may equally well be re- 

 garded, if one is philosophically so dis- 

 posed, as being the marvelous outcome of 

 the accidental conspiracy between molecu- 

 lar structure and a selectively acting en- 

 vironment. Upon the other hand, a living 

 being in which extensive groups of ele- 

 ments, physically more or less distinct and 

 even heterogeneous in character, are in a 

 large way dominated by agents which mold 

 form and direct action, offers to the vital- 

 ist, of whatever type, a realm in which non- 

 physical, ultra-physical or psychic factors 

 and forces may be created and set going to 

 the limit of his bent. 

 Haevard University 



Herbert W. Rand 

 {To be concluded) 



THE GBOWTS OF CEILDBEN 

 Previous investigations have shown that the 

 rate of growth of the body, measured by 

 weight and stature, increases very rapidly 

 until the fifth month of fetal life. From that 

 time on the rate of growth decreases, first 

 rapidly, then more slowly until about four 

 years before the age of puberty. During 

 adolescence the rate of growth is considerably 

 accelerated, and decreases again rapidly Eifter 

 sexual maturity has been reached. Thus the 

 curve of growth represents a line which pos- 

 sesses a very high maximum at about the fifth 

 month of fetal life. It decreases rapidly, and 

 has a second, although much lower maximum 

 shortly before sexual maturity is reached, and 

 not long afterwards reaches the zero point. 



The bulk of the body of girls and boys is 

 approximately equal until the period of adoles- 

 cence. Since this sets in much earlier in the 

 female than in the male, the concomitant ac- 

 celeration also sets in at an earlier time, with 



the result that for a few years girls are larger 

 than boys. 



The periods of most active growth of the 

 various parts of the body differ considerably. 

 Nevertheless, it would seem that the character- 

 istics of the curve of growth as here outlined 

 are repeated in many if not in all organs and 

 parts of the body. For instance, although the 

 head reaches nearly its full size at an early 

 time, so that its rate of growth shows a much 

 raore rapid decrease with age than that of the 

 bulk of the body, there is a slight acceleration 

 of growth during the period of adolescence. 



It might seem, judging from the data just 

 mentioned, that the difference between the 

 sexes does not develop until the period of adol- 

 escence; but a study of the eruption of the 

 teeth which I made a number of years ago, 

 and the more recent interesting investigations 

 by Eotch and Pryor on the ossification of the 

 carpus, show that the difference in physiolog- 

 ical development between the two sexes begins 

 at a very early time, and that in the fifth year 

 it has already reached a value of more than a 

 year and a half. 



I give here a tabular statement of the avail- 

 able observations: 



Ossification of scaphoid 



Ossification of trapezoid 



Eruption of inner permanent in- 

 cisors 



Eruption of outer permanent in- 

 cisors 



Eruption of bicuspids 



Minimum increase of annual growth 



Eruption of canines 



Maximum increase of annual 

 growth 



Eruption of second molars 



Maximum variability of stature 



—1.6 

 —2.0 



—0.5 



—0.6 

 —0.8 

 -2.1 

 -i-0.1 



—2.0 

 —0.4 

 —2.4 



These data are not very accurate and must 

 be considered a first approximation only. 



When we remember that growth depends 

 upon physiological development, it will be 

 recognized that we must not compare the 

 stature of girls of a certain age with that of 

 boys of the same age, but that from the fourth 

 year on a girl of a certain age should be com- 



