INHERITANCE OF FECUNDITY 



197 



Matings: A. With 6 9 9 indicated to be of class 1 = /L1L2 . Fhh. 



9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Observed 11 11 1 



Expected 11.5 11.5 



Mean winter production of 9 9 



in indicated class 64.09 eggs 17.91 eggs eggs 



B. With 5 9 9 indicated to be of class 2 = /L1L2 . FLih. 



9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Observed 18 1 



Expected 19 



Mean winter production of 9 9 



in indicated class 63.56 eggs. 1.00 eggs 



All 9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Obesrved 29 12 1 



Expected 30.5 11.5 



Mean winter production 63.76 eggs 16.50 eggs eggs 



Aside from the two outstanding exceptions the agreement 

 between observation and expectation is excellent. From the 

 records available there is no evident explanation for the two excep- 

 tions (the 'Zero' bird in the A matings, and the 'Under 30' bird 

 in the B matings). Neither of the birds were bred, and hence 

 no help is to be had from the progeny in explaining them. It is 

 reasonable to suppose that the observed records for these birds are 

 somatic fluctuations, but this cannot be demonstrated now. This 

 case illustrates ' an unavoidable difficulty which attends that 

 method of work which first collects data at random and without 

 any theoretical guide, and then later undertakes their analysis. 

 If one had been carrying on the breeding in the present case under 

 the guidance of the hypothesis as to the mechanism of the inherit- 

 ance of fecundity now under discussion, obviously many matings 

 which actually were not carried out would have been made to 

 test out somatically exceptional individuals and so learn their 

 gametic constitution. 



