278 RAYMOND PEARL 



rise to them are produced. One may put the matter in this 

 way: under the conditions which prevail on a large poultry 

 breeding plant it is normal for a certain small percentage of 

 chicks which are abnormal at hatching to be produced. The 

 proportion of such abnormal chicks produced in the breeding 

 season of 1915 from alcoholized parents was no greater than the 

 number produced from untreated parents. In actual fact there 

 tvas exactly one chicken out of 234 hatched from alcohoHzed 

 parents in 1915 that was too weak to band, and was in conse- 

 quence killed at the time of hatching.^ None was deformed. 

 Out of 1527 chicks from untreated parents 16, or 1.0 per cent 

 were weak or deformed or both. 



X. MENDELIAN CHARACTERS IN THE Fj PROGENY 



It is not the intention at this time to enter upon an extended 

 account of the inheritance of characters in the cross Black Ham- 

 burg X Barred Plymouth Rock. We have studied this cross for 

 a number of yeai's and have a great mass of material regarding 

 it, based of course upon non-alcoholic birds. This will no doubt 

 be published at some later date. The only point which it is 

 desired to bring out here is that the phenomena of inheritance, 

 in all of a considerable series of characters, are absolutely identi- 

 cal in the Fi progeny from alcoholic parents and that from 

 untreated parents of the same breeds. 



To demonstrate this fact we may consider the data for a few 

 of the characters studied, taking first color pattern. The regular 

 rule of inheritance of color pattern in the Fi generation of this 

 cross is as follows: 



B. H. cf (self black) X B. P. R. 9 (barrred) = Barred d'd' + non-barred 9 9 



(self black) 



^ This statement may appear difficult to reconcile with statistics given in 

 tables 1 and 5. It is shown in table 1 that 234 chicks hatched, whereas accord- 

 ing to table 5, but 215 were banded. What happened was that, in order to get 

 more extensive statistics on the hatching quality of the eggs, another hatch 

 was brought off on May 12. This produced 18 normal chicks, which were not 

 banded, but immediately discarded. These chicks hence appear in the hatching 

 records, but not in the subsequent data. We have 215 normal banded chicks 

 + 18 normal, but unhanded chicks + 1 abnormal = 234 hatched. 



