THE RATE OF OVULATION IN THE DOMESTIC FOWL 

 DURING THE PULLET YEAR. 



By SAMUEL BRODY. 



{From the Missouri Agricultural Station, Columbia.) 



(Received for publication, January 18, 1921.) 



It is well known among poultrymen that ovulation in the hen is an 

 orderly process with a fairly predictable average production of eggs 

 for each month of the year. The object of this paper is to contribute 

 an idea toward the formulation of an hypothesis concerning the prin- 

 ciples underlying this orderly process of ovulation. This idea is 

 based on a suggestion of Loeb^ that growth, or at any rate the limit- 

 ing factor of growth, is in the nature of an autocatalytic monomolec- 

 ular reaction. The rate of ovulation may reasonably be taken as an 

 index of growth of the eggs, and if the limiting factor of growth of 

 eggs is an autocatalytic reaction, then the rate of ovulation should be 

 expressible by the equation of such a reaction. 



The appHcation of this equation to experimental data is familiar 

 to the chemist.2 Robertson^ and Ostwald^ were the first to apply 

 the equation to the phenomena of growth. In the formulation of 

 the equation it is assumed that the velocity of reaction at any moment 

 is proportional to the quantity of the reacting substance (.4 — x) at 

 that moment, and also to the quantity of the product of the reaction 



^ Loeb, J., Biochem. Z., 1907, ii, 34; 7th Internal. Zool. Cong., 1907; The dynam- 

 ics of living matter, New York, 1906; Univ. California Put., Physiol., 1905-10, 

 iii, 61. 



^ Ostwald, W., Lehrbuch der allgemeinen Chemie, Leipsic, 1903, i. Lewis, G. 

 N., Z. physikal.Chem., 1905, Iii, 310; Dept. Interior, Bureau Gov. Labor., Chem. 

 Lab., No. 30, 1905. 



^Robertson, T. B., Arch. Entwcklngsmechn. Organ., 1908, xxv, 581; Am. J. 

 Physiol., 1915, xxxvii, 1, 74; Principles of biochemistry, for students of medicine, 

 agriculture and related sciences, Philadelphia, 1920. 



^ Ostwald, W., Vortrage und Aufsatze iiber Entwicklungsmechanik Organ- 

 ismen, Leipsic, 1908, v. 



431 



