370 EXPERIMENT STATION RECORD. [Vol. 37 



From the datii at hand the average life of ;i "White Leshorn appctirs to he 

 .»bout six years. The average production of the fourth year is equal to the 

 average total production given for the United States. In general, the average 

 total production is above 500 eggs and the maximum possible production above 

 1,000 eggs. 



A list of 40 references to the cited literature is appended. 



The separate inheritance of plumage pattern and pigmentation in 

 Plymouth Rocks, R. Peabi. {Proct. Hush. Maine, 6 (1916), Xo. 2. pp. J67. 56S; 

 abs. in Mnine Sta. Bui. 251 {1916), p. 3.5'/). — Experiments at the Maine Station 

 are referred to, in continuation of those already noted (E. S. R., 23, p. 674), 

 the results of which are said to indicate that pattern and pigmentation are 

 distinct unit characters in Barred Plymouth Rock fowls. A brief report is 

 also given of crossing experiments with White Plymouth Rock and Cornish 

 Indian Game fowls, the results of which throw light on the probi'.ble nature of 

 the mutation by which the White Plymouth Rock variety was produced, and 

 indicate that White Rocks carry the factor for the barred pattern but lack the 

 hereditary doterniiner for pigment. 



On the effect of continued administration of certain poisons to the domestic 

 fowl, with special reference to the progeny, R. I'kaki. (Proc. Atncr. Phil. Hoc, 

 55 {1916), pp. 24.3-2.5S; Pror. Xnt. AcfuL Sri., 2 {1916), 7, pp. SSO-SSJ, ; abs. 

 in Mnine Stn. Bui. 251 {1916), pp. .?.5.f-.{.).J). — In the invt^tication hero I'e- 

 porled, which has a bearing on the general problem of the origin and causa- 

 tion of new, heritable variations, the method pur.sued was that of exposing 

 .systematically the germ cells of an animal to .something unusual or abnormal 

 in the surrounding conditions and then analyzing the results as shown in the 

 offspring. The specific problems with which the investigation dealt are (1) 

 whether the continued administration of certain narcotic poisons to the do- 

 mestic fowl Induces precise and spi»cific changes in the germinal material sucli 

 as to lead to new, heritable, somatif vnriations; (2) wliotlier. if there is no 

 specific effect, there is a general effect upon the geniiin.il material; (3) the 

 effects in general upon the .^sonia of the treated individual of the continued 

 administration of suHi poisons; and (4) wlu-tlier the somatic effects upon the 

 treated individuals are of a sort to give any clue to the probable origin or 

 mechanism of the germinal changes. 



The foundation stock used in these experiments came from pedigreed strains 

 of two breeds of poultry — Black Hamburgs and Barred Plymouth Rocks. Both 

 of the strains used had been so long podigree-bred and usctl in such a variety 

 of Mendeli!tn experiments l)y the author that their genetic behavior under ordi- 

 nary circumstances was fairly well known. Furthermore, the results of 

 crossing these two breeds reciprocally have boon thoroughly studied. 



Three poisons were used in the work, n;imely, ether, methyl alcohol, and 

 ethyl alcohol. These substances were administered to the binls daily by the 

 inhalation method. 



It is noted that " the egg production of the treated birds and the untreated 

 controls was entirely normal in re.spect of its seasonal distribution, as well as 

 in regard to its amount. There has been no significant difference in the egg 

 production of the treated birds and their untreated control sLsters, either in the 

 total average number of eggs produced per bird nor in the seasonal distribu- 

 tion of this production. The only conclusion which can be drawn from the 

 statistically insignificant difTerences which appear between treatetl and control 

 birds is that the inhalation treatment has not affected the egg production of 

 the birds either favorably or adversely. 



