128 RAYMOND PEARL 



in the series the general methods used in the conduct of the ex- 

 periments will be described in detail. Such a thorough and de- 

 tailed description of the stock used in the work, the experi- 

 mental methods, etc., is beheved to be essential if the reader is 

 to form any adequate idea of the critical value of the results 

 obtained. The WTiter is very anxious that any one who reads 

 the papers in this series shall have the opportunity of knowing 

 exactly how the work was done. If then he desires to contro- 

 vert the conclusions reached he will at least be saved the trouble 

 of interpreting the results on the basis of totally erroneous 

 suppositions as to the technique of the work, the stock used, etc. 



The second paper in the series will contain an account of the 

 effect of the treatment with alcohol upon the treated individuals 

 themselves. 



The third paper in the series will set forth the results obtained 

 regarding the effect of the treatment of the parents upon the 

 progeny. 



Inasmuch as these three papers will appear in succession in 

 the same journal it has seemed desirable, in the interest of 

 economy of space, to print the numbered hst of bibhographical 

 titles cited only once and in connection with this, the first paper 

 in the series. The numbers following citations in the next two 

 papers in the series will, therefore, be understood to refer to 

 the bibhography appended to the present paper. 



II. MATERIAL AND METHODS 



A. General Plan 



The general plan of this investigation involves some fea- 

 tures which have not been incorporated in earUer researches in 

 this general field. In the first place, it was thought desirable 

 to use two pure breeds of poultry for the foundation stock in the 

 experiments rather than one, and in consequence of this make 

 the offspring of the treated animals Fi crossbreds rather than 

 pure-bred birds. The primary consideration in favor of this 

 plan was that, by its adoption, a much more manifold oppor- 

 tunity seemed Ukely to be given to test any putative influence 



