76 



THE RATE OF GROWTH 



[CH. 



velocity; but after that date, though growth is still rapid, its 

 velocity tends to fall away. There is a shght break between our 

 two separate sets of statistics at the date of birth, while this is 

 the very epoch regarding which we should particularly like to 

 have precise and continuous information. Undoubtedly there is 

 a certain shght arrest of growth, or diminution of the rate of 

 growth, about the epoch of birth : the sudden change in the 



500 

 mm. 



400 



300 



200^ 



100 



2 4 6 8 10 



months 



Fig. 9. Curve of pre-natal growth (length or stature) of child; and 

 correspondmg curve of mean monthly increments (mm.). 



Fehling and others. But it is plain that the very rapid increase of the monthly 

 weights, approximately in the ratio of the cubes of the corresponding lengths, 

 would tend to conceal any such breach of continuity, unless it happened to be very 

 marked indeed. Moreover in the case of Jackson's data (and probably also in 

 the others) the actual age of the embryos was not determined, but was estimated 

 from their lengths. The following is Jackson's estimate of average weights at 

 intervals of a limar month : 



Months 0123456 7 8 9 10 



Wt in gms. -0 -04 3 36 120 330 600 1000 1500 2200 3200 



