INHERITANCE OF FECUNDITY ' 259 



ters. The reason is because of the impersonal and objective 

 character of the original records in the case of fecundit3^ The 

 original trap-nest records on which this whole study is based were 

 made by Mr. F. Walter Anderson. He had neither knowledge 

 of, nor interest in, the use of which any particular record or set of 

 records were to be put. He was solely concerned to make as 

 accurate record as possible of the la^'ing of each individual hen. 

 The system of record taking used is such that it was impossible 

 for him to have any notion of what the total production of any 

 given bird up to a particular date had been. The chance for 

 bias or personal equation influencing results is excluded when, 

 as in the present case, one person makes the basic records, and 

 has nothing whatever to do with their analysis, while another 

 person analyzes the data but has nothing directly to do with their 

 collection. 



Another safeguard on the results in this same direction, and also 

 in another, is found in the fact that birds belonging to the same 

 family (full sisters) were not given identifying numbers which 

 would make it possible to be certain or even to surmise that they 

 were sisters, without consultation of the pedigree records. The 

 numbering of the birds for identification each year was purely at 

 random and without any regard whatsoever to relationship. 

 Furthermore members of the same family were distributed at 

 random through the different pens and houses. No attempt is 

 ever made, from the day the chicks hatch, to keep the birds from 

 one family together. Indeed it is important that they be scat- 

 tered at random through the flock in order to insure unifonn.ity of 

 average environmental conditions. 



The writer has no desire to generalize more widely from the 

 facts set forth in this paper than the actual material experimen- 

 tally studied warrants. It must be recognized as possible, if not 

 indeed probable, that other races or breeds of poultry than those 

 used in the present experiments may show a somewhat different 

 scheme of inheritance of fecundity. The directions in which devi- 

 ations from the plan here found to obtain may, at least a priori, 

 most probably be expected are two. These are: (a) differences 

 in different breeds in respect to the absolute fecundity value or 



