METHODS FOR THE MANIPULATION OF OVA 67 



on the bulb when the opening in the tube is closed over. 

 No amount of pressure on the bulb will expel the ova if 

 the opening is not closed. Extreme care should be taken to 

 expel only the ova and the fluid containing them. If air is 

 also pumped into the tubes it often blows the eggs down too 

 far into the tubes or even into the uterus. Excessive fluid 

 acts in the same way. 



The writer (in collaboration with Dr. E. V. Enzmann) 

 has also transplanted mouse ova into the fallopian tubes. 

 Here it is necessary to slit the capsule and expose the tubal 

 opening, which is slightly wider than at the ampulla, but 

 not as wide as the rabbit's fimbriated opening. The tubes 

 are observed under a dissecting microscope and the opening 

 exposed by manipulation with iris or watchmaker's forceps. 

 The delicate mouse ova are best handled in warm Ringer- 

 Locke solution plus serum. 



Nicholas (1933a) has transplanted rat ova from the fal- 

 lopian tubes into the uterus. In this case the tubes are 

 excised at the isthmus and the ova expelled from a capillary 

 pipette into the uterine lumen. 



