CYCLIC CHANGES IN THE OVARIES AND UTERUS OF THE SOW, ETC. 



123 



METHODS OF PREPARATION. 



Since recovery of the ova and early embryos by means of serial section of the 

 tubes and uteri is out of the question in so large an animal as the sow, a procedure 

 was devised which grew out of a suggestion by Professor Evans based upon the 

 practice of Martin Barry (1839), one of the earlier workers on the problems of 

 o vulation, who obtained the tubal ova of rabbits by stroking the tubes with a rod in 

 order to express their contents into a dish. Our improvement, which we have 

 since found had already been used by Sobotta (1897) and others, consists simply 

 in washing out the Fallopian tubes with a stream of isotonic salt solution. 



Uterine cornu. 72 cm. 



Corpus uferi 5cm. /s 



Tube 

 Liq.Laium 



FG. 1. Diagram showing form and dimensions of the uterus and Fallopian tubes of the sow, drawn 

 from an average specimen taken from a young mature animal. 



Reference to figure 1 will make the following description clear. The Fallopian 

 tube is freed from the mesosalpinx by cutting the latter off close to the tubal border 

 and is detached from the uterus at the junction of the tube and cornu. The now 

 straightened tube is suspended by one hand over a Syracuse dish and is filled, by 

 means of a pipette, with sufficient normal saline solution to distend the lumen 

 moderately. The narrow uterine end of the tube prevents the fluid from draining 

 into the dish until .the tube is gently "milked" out with the fingers. If ova are 

 present they usually pass out with the first drops of fluid, but in some cases four or 

 five washings are necessary to recover all that are present in the tube. The ova 

 are located in the dish by inspection of the washings under a low-power microscope. 



This method is rather awkward when applied to the whole uterus because of the 

 large quantity of fluid required to distend the canal, amounting often to 300 c.c. For 

 this reason recourse has been had to a plan by which a small amount of fluid (10 to 

 30 c.c.) is caused to distend successive short portions of the uterus. The uterine 

 cornu having been uncoiled by cutting it from the mesometrium, a stout clamp is 

 applied to it a few centimeters below the ovarian extremity and the distal portion is 

 dilated with the salt solution; another clamp is now applied a few centimeters 

 below the first, which is removed, and the fluid is forced by gravity and by digital 

 pressure into the second section of the uterus, which is thus in turn distended, and so 

 on. In this manner any ova or unattached embryos which are present are picked up 

 and carried along until the fluid has passed through the whole length of the uterus, 

 and are then deposited with the washings in one or two Syracuse dishes. 



