PHYSIOLOGY OF THE OVIDUCT 417 



THE EFFECT OF OPERATIONS ON THE OVIDUCT UPON ITS GROWTH 

 AND ABILITY TO FUNCTION 



1. Diminishing the caliber of the duct 



Four operations were performed to test the effect of dimin- 

 ishing the diameter of the oviduct. In cases 21 and 22 the 

 size of the albumen secreting region of the duct was decreased 

 for several centimeters by taking a tuck in the wall. In case 

 23 the size of the shell gland was diminished by cutting out a 

 piece of the wall. In case 24 the shell gland was made smaller 

 by inverting a longitudinal portion of the wall. All these birds 

 laid normal eggs. In size and shape these eggs were within 

 the range of variation shown by the eggs of unoperated birds 

 of the same breed. At autopsy the stitches which had made 

 the tucks had either pulled out (cases 21 and 24) or the tuck 

 was preserved only as a ridge on the muscular wall (case 22). 

 In case 23 where a piece of the wall of the shell gland had been 

 removed this part was of normal shape. It looked a little small. 

 This bird, however, had laid eggs fully up to the average size 

 for her breed. 



The operations attempted did not perceptibly influence the 

 size or shape of the egg. Many well controlled experiments 

 would be necessary to demonstrate that it is impossible to alter 

 the size and shape of the egg by diminishing the diameter of 

 the tube. In three of the four operations the size of the tube 

 was not permanently diminished because the stitches did not 

 hold. 



2. Closing the duct at various levels 



When the funnel is closed by sewing the lips, or by ligating 

 the ostium, yolks cannot enter the duct. Yet in such cases the 

 duct passes through the normal phases of reproduction. In 

 cases 1 to 6 the oviducts were in laying condition at the time the 

 ostium was closed, either by sewing the lips (case 1) or ligating 

 the funnel mouth (cases 2 to 6). At the time of autopsy thir- 

 teen days to two months later the oviduct of each bird was 

 in a condition of reproduction corresponding to the condition 

 of the ovary. Two of these birds had ovulated into the body 



