422 RAYMOND PEARL AND M. R. CURTIS 



SUMMARY 



1. Neither the Ugation, section, nor entire removal of the 

 oviduct causes the degeneration or prevents the further growth 

 of the ovary. 



2. The pressure of the enclosing funnel is evidently not neces- 

 sary to ovulation since yolks are ovulated into the body cavity 

 after the ostium is sewed or ligated or after the entire duct is 

 repioved. 



3. Internal pressure due to continued yolk formation is prob- 

 ably the most important factor in the normal rupture of the 

 follicle, since closing the funnel or removing the duct apparently 

 does not greatly delay ovulation. 



4. There are cases of unoperated birds with normally func- 

 tioning ovaries, and oviducts apparently capable of functioning, 

 which do not produce eggs because of some anatomical or phys- 

 iological condition of the mouth of the oviduct which prevents 

 the entrance of the yolk. 



5. The fate of yolks or eggs set free in the body cavity 

 depends apparently upon the physiological vigor of the bird. 

 First, they may cause serious metabolic disturbances which re- 

 sult in the death of the bird; second, they may be absorbed 

 rapidly from the general peritoneal surface; or third, they may be 

 walled off by peritoneum and then absorbed. 



6. The material from the resorbed yolks or eggs is apparently 

 utilized in body metabolism since all such birds which were in 

 good health at the time of autopsy were very fat. 



7. The removal of the greater portion of an oviduct does not 

 cause the atrophy of any remaining portion. 



8. The whole or any remaining part of an oviduct sewed at 

 the funnel, ligated at any level, or with parts removed, passes 

 through growth and cyclic changes coordinated \yith changes in 

 the ovary exactly as an unoperated duct. 



9. The stimulation of the advancing egg is necessary for the 

 discharge of the secretion of the duct, since a duct closed at any 

 level functions only to the point where the passage is interrupted. 



