114 RAYMOND PEARL AND MAYNIE R. CURTIS 
ad 
iS} 
8 
PEACENTAGE OF TOTAL ALBUMEN 
N 
8 
HOURS 
6 Ta 
UTERUS 
Fig.4 Diagram showing what percentage of the total amount of albumen 
present in the normal laid egg of the domestic fowl is present at successive levels 
in the oviduct. The smooth curve is the parabola for which the equation is given 
in the text. 
the manner in which the plotted points were determined. In the 
first place it has been found in our work here that when a hen is 
laying regularly one egg per day ovulation occurs at approximately 
the same time as laying. That is the odcyte which will be laid 
as a completed egg tomorrow enters the infundibulum at the 
time when today’s passes through the vagina and is laid. This 
then is taken as a fundamental datum in the calculation of the 
rate of passage of the egg down the oviduct. 
The mean of all available observations made in this laboratory 
gives 3.2 hours as the time required for the passage of the egg 
through the ‘albumen portion’ of the oviduct. This includes the 
total time from the entrance of the egg into the infundibulum to 
its entrance into the isthmus. This agrees very well with the 
statements of earlier workers® who generally give the time spent 
in the albumen portion of the duct as ‘about’ three hours. 
6 Cf. Lillie, F. R. The Development of the Chick. New York, 1908, pp. 23-25. 
