EVIDENCE OF GERM CELL SELECTION 397 



Those tending to produce chicks that were 



1. Brachydactyl, polydactyl, white. 



2. Brachydactyl, polydactyl, black. 



3. Brachydactyl, not polydactyl, white. 



4. Brachydactyl, not polydactyl, black. 



5. Not brachydactyl, polydactyl, white. 



6. Not brachydactyl, polydactyl, black. 



7. Not brachydactyl, not polydactyl, white. 



8. Not brachydactyl, not polydactyl, black. 



It will be apparent that by the inspection of any chick it could 

 be determined at once to which of these eight classes the sperm 

 cell involved in its production had belonged. 



C. The hens began laying on March 6 and eggs were saved 

 for the control experiment from that date to April 8, during 

 which period 106 eggs were produced (table 2). Two of these 

 were accidentally cracked and therefore discarded. One, 

 laid April 3, was non-fertile. 



A. The period of alcohol treatment followed immediately 

 upon the control period. The first treatments, of 1 hour and 

 2 minutes and 1 hour and 4 minutes, were given on April 8, 

 and the final treatment on June 11. This bird was kept in the 

 inhalation chamber for two periods of at least an hour each 

 every day except May 5, when in the absence of the writer an 

 attendant misunderstanding directions gave only a single one- 

 hour treatment. In the period of sixty-five days no. 27 was 

 kept in the alcohol vapor for a total of 143 hours and 56 minutes. 

 He, showed the usual responses: hyperexcitability, occasional 

 weakness in the legs, and crowing ability invariably impaired 

 for many minutes. He was removed from the breeding pen 

 on June 12. 



Eggs were saved from April 9 to June 19. During this period 

 191 were laid, of which eleven, unfortunately, were lost through 

 breakage or otherwise (table 2). The two recorded as non- 

 fertile were laid on April 21 and June 14, respectively. 



Experiment 3. (February 9, 1918, to June 12, 1918). The 

 heterozygous parent (no. 28) hatched in June, 1917, from an 

 egg used in experiment 1-A. ^ He was very similar to male no. 

 27 described above; in fact, these two males were selected 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 28, NO. 3 



