EXPERIMENTS WITH ALCOHOL 139 



to draw the really quite erroneous conclusion that the alcohol 

 caused the poor laying. 



Summarizing the data in table 2 it appears that there were 

 six females and one male treated with ethyl alcohol; four fe- 

 males and one male treated with methyl alcohol; and five fe- 

 males and one male treated with ether. Of the females treated 

 with ethyl alcohol, one (1574) was approximately 1^ years old 

 at the beginning of the treatment. The other five (1481, 1482, 

 1483, 1484 and 1889) were from seven to ten months old at the 

 beginning of the treatment. In the case of the methyl-alcohol 

 birds, one (1575) was a year and a half old hen, and the other 

 three (1486, 1487 and 1492) were pullets. In the case of the 

 other birds, two (1572 and 1573) were hens a year and a half 

 old and the other three (1485, 1490 and 1491) were pullets. All 

 of the male birds used were cockerels from seven to eight months 

 old at the beginning of the treatment. In reading table 2 it 

 should be noticed that the first column headed 'Ex mating' 

 denotes the number of the mating from which the birds in the 

 following colunm came (Pearl and Surface, 26). The last 

 column headed 'In mating No.' gives the numbers of the mat- 

 ings into which the various birds entered. Of course all of the 

 birds out of the same mating (i.e., having the same mating 

 number in the first colunm) will be full sisters. 



In examining the results of such an investigation as the pres- 

 ent one with the purpose of reaching a critical conclusion as to 

 their meaning there is probably no one piece of information 

 which is more earnestly desired by the experienced geneticist 

 than a clear and comprehensi\'e statement as to just how the 

 foundation stock which went into the experiment was bred. 

 This information is commonly denied the reader, not because of 

 any malicious intent to suppress data, but simply because the 

 experimenter himself lacks this knowledge. The inexperienced 

 worker in genetics, and the student of other fields of biology, 

 are not Hkely to realize the verj^ great importance of the point 

 here involved in reaching a critical interpretation of results. 

 'Controls' in the ordinary sense may be totally misleading in a 

 genetic experiment, as for example, when the experimented 



