92 NATURAL INHERITANCE. [CHAP. 



were so few in number that I could not well afford to lop 

 off more. These Tables were constructed by registering 

 the differences between each possible pair of brothers in 

 each family : thus if there were three brothers, A, B, 

 and C, in a particular family, I entered the differences 

 of stature between A and B, A and C, and B and C., 

 four brothers gave rise to 6 entries, and five brothers to 

 10 entries. The larger Fraternities were omitted, as the 

 very large number of different pairs in them would 

 have overwhelmed the influence of the smaller Frater- 

 nities. Large Fraternities are separately dealt with in 

 Table 14. 



We can derive some of the constants by more than 

 one method ; and it is gratifying to find how well the 

 results of different methods confirm one another. 



Mid- Stature of the Population. The Median, Mid- 

 Stature, or M of the general Population is a value of 

 primary importance in this inquiry. Its value will be 

 always designated by the symbol P, and it may be 

 deduced from the bottom lines of any one of the three 

 Tables. I obtain from them respectively the values 

 6 8 '2, 68' 5, 6 8 '4, but the middle of these, which is 

 printed in italics, is a smoothed result. It is one of the 

 only two smoothed values in the whole of my work, and 

 was justifiably corrected, because the observed values 

 that happen to lie nearest to the Grade of 50 ran out of 

 harmony with the rest of the curve. It is therefore 

 reasonable to consider its discrepancy as fortuitous, 

 although it amounts to more than 0'15 inch. The 



