142 



THE KATE OF GROWTH 



[CH. 



and V/T or L/T- , represents (as we have learned) the acceleration of 

 growth, this being simply the "differential coejficient," the first 

 derivative of the former curve. 



Now, plotting this acceleration curve from the date of the 

 first measurement made three days after the amputation of the 

 tail (Fig. 36), we see that it has no point of inflection, but falls 

 steadily, only more and more slowly, till at last it comes down 

 nearly to the base-line. The velocities of growth are continually 

 diminishing. As regards the missing portion at the beginning of 

 the curve, we cannot be sure whether it bent round and came dowii 



2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 



da^s 



Fig. 37. Logarithms of values shewn in Fig. 36. 



to zero, or whether, as in our ordinary acceleration curves of growth 

 from birth onwards, it started from a maximum. The former is, 

 in this case, obviously the more probable, but we cannot be sure. 

 As regards that large portion of the curve which we are 

 acquainted with, we see that it resembles the curve known as 

 a rectangular hyperbola, which is the form assumed when two 

 A''ariables (in this case V and T) vary inversely as one another. 

 If we take the logarithms of the velocities (as given in the table) 

 and plot them against time (Fig. 37), we see that they fall, approxi- 

 mately, into a straight line; and if this curve be plotted on the 



