156 MAINE AGRICULTURAL EXPERIMENT STATION. I9II. 



only to be said that the net outcome of the experiment was to 

 show that there was no steady or fixed improvement in average 

 flock production after the long period of selection. There was 

 no permanently cumulative effect of the eight (in the last year) 

 generations of selected ancestry. So far from there having been 

 an increase there was actually a decline in mean tgg production 

 concurrent with the selection, taking the period as a whole. 

 During parts of the selection period, however, as for example 

 the years 1899-1900 to i90i-'o2, inclusive, and the years 1902- 

 '03 to i905-'o6, inclusive, an improvement from year to year 

 was to be noted, but in each case the flock dropped back in in- 

 tervening years. This is an important point, the meaning of 

 which is now clear. The flock average from year to year 

 depended largely upon whether the breeders of the year before 

 had had their high fecundity genetically represented or only 

 somatically. In some years the selection was fortunate in get- 

 ting nearly all the breeders from good (?'. e., "high production") 

 genotypes or from good combinations of genes. In other years 

 just the opposite thing happened; the high layers chosen as 

 breeders came from low genotypes or combinations of genes. 

 The general upshot was that while the selection of high layers 

 merely as such was systematic year after year the result attained 

 in the general flock production was entirely haphazard and 

 uncertain. This is exactly what would be expected on the geno- 

 type hypothesis, but not on the "statistico-ancestral." 



TABLE I. 



Mean Winter (November i to March i) Egg Production during the 

 Selection Experiment. 



Mean Winter 

 Year Production 



1899-19GO 41.03 



1900-01 ."^Z-SS 



1901-02 45.23 



1902-03 26.01 



1903-04 26.55 



1904-05 35-04 



1905-06 40.66 



1906-07 21.44 



1907-08 1 5.92 



The actual course of the average winter egg production (not 

 hitherto published)^ during the period is given by the figures of 

 Table I and shown graphically in fig. 80. 



