The Growth of the Body in Man. 



161 



1 = A;W n , where n has the value 0*33 and the value of k for the grouped boys 

 is 23-23. 



For the individual boys the average value of k is 23*33. Its greatest value 

 in the series (25*27) exceeds the average value by 8'32 per cent., and its least 

 value (2T08) falls below the average value by 9 - 69 per cent. 



Using the average value of k (23*33) and the value 0*33 for n, the 

 theoretical body-length of each individual has been calculated from the 

 body-weight by means of the formula 



I = 23-33 W 0,33 . 



From consideration of space the figures have not been tabulated, but they 

 show an average percentage difference between the calculated body-length 

 and that actually observed for the individual boys of only 2 - 63 per cent., and 

 a mean deviation calculated by the method of least squares of 3*378 per cent. 



Accordingly it may be taken that the formula holds very satisfactorily for 

 boys. In these boys, however, the ages do not exceed 15 years, nor the 

 weights 51,000 grm. (8 stone 1 lb.). Hence before it can be assumed that the 

 formula holds up to adult age some further evidence is desirable. This may 

 be found in a study of the data provided by Dr. Schuster's measurements of 

 undergraduates, along with certain measurements of undergraduates made by 

 myself. 



Dr. Schuster's data consist of the measurements of two series of under- 

 graduates during their first year at the University, a first series of 1000 

 individuals and a second series of 500. They are presented in Tables III 

 and IV as grouped by myself. 



In dealing with these figures for grouped undergraduates it was necessary 

 at the outset to apply two corrections. In the first place Schuster's 

 measurement of body-length is the " sitting height " as measured on a fixed 

 seat. But from observations which I made on a series of individuals 

 measured for the purpose in a similar manner, and also in the manner 

 described in this paper, it appeared that the sitting height by the former 

 method is always greater by from 2 to 3 per cent, than the measurement of 

 length on which the present investigation is based. Between the limits 



2 and 3 per cent, the precise value of the excess measurement depends very 

 much on how the individual seats himself, and on the degree to which he 

 lifts himself on his thigh muscles as explained in the section on method of 

 measurement. 



Accordingly I have taken the mean of these limits {i.e. 2*5 per cent.) as 

 the amount to be deducted from the average sitting heights to obtain the 

 true value of the average body-lengths for the groups. The second correction 



