194 THE MENDEL JOURNAL 



inheritance has led me to the opinion that the so-called 

 " law of ancestral inheritance " probably has very 

 little relation to the actually important and essential 

 facts of inheritance in plants and animals. On the 

 contrary, I am led, primarily as a result of the investi- 

 gations carried on in this laboratory during the past 

 three years regarding the inheritance of, and effect of 

 selection upon a character exhibiting fluctuating variation 

 (egg production or fecundity in fowls)* to believe that 

 inheritance is in general in accordance with Johannsen's 

 " pure line " scheme. The fact of " line " inheritance 

 for a character showing such wide fluctuations ( = phaeno- 

 typic variation, Johannsen) as does egg production 

 is made very obscure and difficult of analysis as 

 compared with the characters of self-fertilising plants, 

 by the circumstance of sexual reproduction. But of 

 the fact there can, in my judgment, be no doubt. Further- 

 more, I may say that it is my opinion that the general 

 viewpoint respecting inheritance comprised under the 

 idea of " pure hnes," which is so clearly and forcibly 

 set forth by Johannsen in his recent book, is the most 

 fundamental, accurate, and comprehensive view of 

 heredity yet proposed. The relation of Mendelism to 

 this view is evident. 



" Ardent Mendelian " calls me an " ardent bio- 

 metrician." If by this he means merely (which he 

 obviously does not) that I am an ardent advocate of 

 the proper use of mathematical methods in biology, 

 including Mendelian studies, I accept the designation. 

 If, on the contrary, he means (which he obviously does) 

 that I " ardently " uphold the views regarding inheritance 

 which he attributes to me he is in most complete error. 



The " ardent "' espousal of schools of biological 

 thought seems to me to be somewhat absurd. L^nless 

 I quite mistake the import of the scientific method it 



* Cf . in particular the following papers : Pearl, R. , and Surface, F. M. 

 A Biometrical Studj' of Egg Production. Part I. Variation in Annual 

 Egg Production. U.S. Dept. Agr. Bur. An. Ind. Bulletin 110, pp. 1-80, 

 1909. Studies of the Physiology of Reproduction in the Domestic Fowl. 

 II. Data on the Inheritance of Fecundity Obtained from the Records of 

 Egg Production of the Daughters of " 200-egg " Hens. Me. Agr. Expt. 

 Stat. Bulletin 166, pp. 48-84, 1909. Is There a Cumulative Efft ct of Selec- 

 tion ? Data from the Study of Fecundity in the Domestic Fowl. Ztschr. 

 f. Abst. u. Vererb.-Lehre, loc. cit. 



