16 



INTRODUCTORY REMARKS, 



Chap. I 



age, were subjected from first to last to the same 

 conditions, and were descended from the same parents. 

 When only from two to six pairs of plants were 

 measured, the results are manifestly of little or no 

 value, except in so far as they confirm and are con- 

 firmed by experiments made on a larger scale with 

 other species. I will now give the report on the seven 

 tables of measurements, which Mr. Galton has had the 

 great kindness to draw up for me. 



" I have examined the measurements of the plants with care, 

 and by many statistical methods, to find out how far the means 

 of the several sets represent constant realities, such as would 

 come out the same so long as the general conditions of growth 

 remained unaltered. The principal methods that were adopted 

 are easily explained by selecting one of the shorter series 

 of plants, say of Zea mays, for an example." 



Zea mays {young plants'). 



