l66 MAINE AGRICULTURAL EXPERIMENT STATION. I913. 



devoted to shell formation Clearly much more albumen is 

 added to the egg in the uterus than in the isthmus. This,, of 

 course, does not necessarily mean any more rapid rate of se- 

 cretion in the uterus, because of the time element involved. The 

 egg stays much longer in the uterus than in the isthmus. 



The rate of albumen secretion per unit of time as the egg 

 passed down the oviduct was determined, and was found to be 

 expressed by a parabola, 



3'— 17.591 5,a- — .8171.1- — 0.4164 

 in which y denotes percentage of albumen and x tim.e in hours 

 during which the egg has been in the oviduct. This relation is 

 shown in Figure 66. 



There is scarcely any diminution in the rate of secretion until 

 nearly the total amount has been acquired by the egg. There is 

 not the slightest evidence of any break in the rate of secretion 

 of albumen after the egg leaves the so-called "albumen portion" 

 of the duct. From the time the yolk enters the upper end of 

 the "albumen portion'' there is a gradual diminution of the rate 

 of secretion of albumen, giving rise to the parabolic curve. But 

 there is no sudden change. The egg gets more than half of 

 its total albumen after it leaves the "albumen portion" of the 

 duct and it takes this at nearly the same rate as it did the 

 earlier part. 



While the two lines of evidence already presented amply 

 demonstrate that the "thin" albumen is added to the egg after 

 it leaves the so-called albumen portion of the duct, it seemed 

 advisable, because of the novelty of the results, to collect still 

 further evidence of another kind. This evidence has to do with 

 the nitrogen content of the albumen in eggs taken from different 

 levels of the oviduct. 



The point of greatest interest and importance in connection 

 with these chemical data hinges upon the absolute amount of 

 nitrogen in the albumen. Since it is solely the "thin" albumen 

 layer which is added after the egg leaves the so-called albumen 

 portion of the oviduct the possibility is at once suggested that 

 what happens in the lower portions of the duct is not a true 

 secretion of another albumen layer but merely a taking up of 

 of water from the blood by osmosis, and a dilution or partial 

 solution of the "thick" albumen already present. Such a view 



