1 68 mains; agricultural experiment station. 1913. 



Summary of Results. 



Putting all the evidence together the following account of the 

 processes by which the hen's egg acquired its protective and 

 nutritive coverings summarizes the results of the present study. 



1. After entering the infundibulum the yolk remains in the 

 so-called albumen portion of the oviduct about three hours and 

 in this time acquires only about 40-50 per cent by weight of its 

 total albumen, and not all of it as has hitherto been supposed. 



2. During its sojourn in the infundibular and albumen por- 

 tions of the duct the egg acquires its chalazse and clialaziferous 

 layer, and the ''thick" albumen layer. 



3. Upon entering the isthmus, in passing through which por- 

 tion of the duct something under an hour's time is occupied 

 instead of three hours as has been previously maintained, the 

 egg receives its shell membrane by a process of discrete depo- 

 sition. 



4. At the same time, and during the sojourn of the egg in 

 the uterus, it receives its outer layer fluid, or "thin" albumen 

 which is by weight 50-60 per cent O'f the total albumen. 



5. This "thin" albumen is taken in as a dilute fluid by 

 osmosis through the shell membranes already formed. The 

 fluid albumen added in this way diffuses into the dense albu- 

 men already present, dissolves some of the latter and so brings 

 about its dilution in some degree. At the same time the fluid 

 albumen is made more dense in this process of diffusion, and 

 comes to have the consistency of the thin albumen layer of the 

 normal laid egg. The fluid albumen taken into the egg by os- 

 mosis is a definite secretion of glands of the isthmus and uterus. 



6. The addition of albumen to the egg is completed only 

 after it has been in the uterus from 5 to 7 hours. 



7. Before the acquisition of albumen by the egg is completed 

 a fairly considerable amount of shell substance has been 

 deposited on the shell membrane. 



8. For the completion of the shell and the laying of the egg 

 from 12 to 16, or exceptionally even more, hours are required. 



