author's abstract of this paper issued 

 by the bibliographic service, june 27 



STUDIES ON THE PHYSIOLOGY OF REPRODUCTION 

 IN THE DOMESTIC FOWL 



xviii. further observations on the anatomical basis of 



fecundity! 



RAYMOND PEARL AND WILLIAM FREEMAN SCHOPPE 



TWO FIGURES 



INTRODUCTION 



Some eight years ago one of us- published the results of some 

 counts of the visible oocytes upon the ovaries of domestic fowls. 

 The number of birds dealt with at that time was statistically 

 small, amounting to but seventeen. The problem to which 

 attention was directed in this earlier work was stated as follows : 



''To what extent are observed variations in fecundity (i.e., in 

 the number of eggs laid) to be referred to anatomical differences? 

 In other words, does the ovary of a high-producing hen, with, for 

 example, a winter record of from 75 to 115 eggs, contain a larger 

 number of oocytes than does the ovary of a hen which is a poor 

 producer, laying no eggs in the winter period and perhaps but 

 10 or 15 eggs in the year?" 



The purposes of the present work were to extend the observa- 

 tions to a larger number of birds; to check the general reliability 

 of the results by getting independent counts of another observer; 

 to get data on wild birds, and to carry out certain experiments 

 on ovarian regeneration. The counts of the present series will 

 be combined with the earlier data and the whole submitted to 

 certain biometrical treatment. 



' Papers from the Department of Biometry and Vital Statistics, School of 

 Hygiene and Public Health, Johns Hopkins University, no. 24. 



The observations on which this paper is based were made some years ago at 

 the Maine Agricultural Experiment Station. The paper has been completed by 

 the senior author. 



2 Pearl, R. The mode of inheritance of fecundity in the domestic fowl. Jour. 

 Exp. Zool., vol. 13, pp. 153-268, 1912. 



101 



